Search

A Ni-catalyzed reductive dialkylation of 8-aminoquinoline-tethered aliphatic alkenes with two unactivated alkyl electrophiles is disclosed here. Key to the development of this transformation is the combination of primary alkyl (pseudo)halides and secondary alkyl iodides that produce products in a single regioselective manner. The reaction exhibits good functional group compatibility, and its synthetic utility was demonstrated by the concise synthesis of the precursors of biologically relevant molecules.

Purpose: As a critical component of the wind turbine drive train, the bearings are easy to fail under the complex environment of variable working conditions and loads in long-term operation. So it is essential to carry out a study targeting at fault diagnosis on it to improve the safety and reliability of the whole wind turbine operating. Methods: This paper presents a kind of bearing fault diagnosis method for wind turbines based on convolutional neural network (CNN) and sparrow search algorithm (SSA) optimized extreme learning machine (ELM). First, the wavelet time-frequency diagram (WTD) is constructed by using the continuous wavelet transform (CWT) to the original vibrational signal of the wind turbine bearing. Then, the WTD is input into deep learning CNN for extracting features. Finally, the SSA-ELM classifier is constructed by searching the optimal parameters of ELM with SSA, and the extracted features are put into SSA-ELM to identify different fault types. Results: The proposed CWT-CNN-SSA- ELM method is experimentally validated by two bearing datasets and compared with other methods. The result shows that the method has better diagnosis capability. Conclusion: In this paper, a wind turbine bearing fault diagnosis method based on CNN and SSA-ELM is proposed. The approach is able to well extract fault features and classify and identify the bearing data under variable working conditions and time-varying speed with good generalization ability.

Herein, the 2,4-dinitrophenyl functional group acting as the thiophenol reactive site was introduced into a carbazole–chalcone fluorophore to synthesize probe-CCF2, which could result in a remarkable increase in fluorescence when reacting with thiophenols. The selectivity and accuracy of probe-CCF2 were investigated with thiophenols, hydrosulphide salt, aliphatic thiols, glutathione, cysteine, anions and metal cations. Probe-CCF2 exhibited a detection limit of 37 nmol/L (R2= 0.9951), a remarkable Stokes shift of approximately 130 nm, and a brief response time of 9 min with a remarkable increase in fluorescence of 90-fold. Probe-CCF2 was applied for thiophenol detection in water samples and imaging in living cells successfully, with high sensitivity and excellent selectivity.

ABSTRACTRNA and protein are interconnected biomolecules that can influence each other’s life cycles and functions through physical interactions. Abnormal RNA–protein interactions lead to cell dysfunctions and human diseases. Therefore, mapping networks of RNA–protein interactions is crucial for understanding cellular processes and pathogenesis of related diseases. Different practical protein-centric methods for studying RNA–protein interactions have been reported, but few robust RNA-centric methods exist. Here, we developed CRISPR-based RNA proximity proteomics (CBRPP), a new RNA-centric method to identify proteins associated with an endogenous RNA of interest in native cellular context without pre-editing of the target RNA, cross-linking or RNA–protein complexes manipulation in vitro. CBRPP is based on a fusion of dCas13 and proximity-based labelling (PBL) enzyme. dCas13 can deliver PBL enzyme to the target RNA with high specificity, while PBL enzyme labels the surrounding proteins of the target RNA, which are then identified by mass spectrometry.

Zircon is a common accessory mineral in various rocks, especially in the crustal ones. It is the best mineral for U-Pb dating. Meanwhile, trace elements and isotopes of the mineral can also provide much information concerning the formation and evolution of rocks. There are a growing number of reports of zircon existing in mantle peridotite. However, it is generally considered that zircon is unlikely crystallized in ultrabasic rocks due to SiO2-unsaturation. In this paper, the SiO2activity and zircon/baddeleyite transition curve at different conditions were calculated through thermodynamic phase equilibrium modeling, to reveal the main factors affecting the SiO2activity and the stability of zircon/baddeleyite in ultrabasic and basic rocks, especially in mantle peridotite. These results provide a thermodynamic basis for interpreting the genesis and significance of zircon in mantle rocks. That is, the SiO2activity is mainly controlled by stable mineral assemblages and temperature-pressure conditions. The orthopyroxene+olivine assemblage in peridotite as an effective buffer restricts the SiO2activity in a relatively high range with a small variation. The upper temperature limit of zircon can reach more than 1500°C with this mineral assemblage. During the low-temperature serpentinization of peridotite, the replacement of olivine and pyroxene by serpentine can result in a significant decrease of SiO2activity, and baddeleyite can be stabilized at <530°C and < 2.7 GPa. When peridotite is strongly metasomatized by the SiO2-bearing fluid, the addition of SiO2can increase its activity and make zircon stable at low temperatures. The SiO2activity in ultrabasic-basic rocks is not only positively correlated with the SiO2content but also negatively correlated with the Ca and Na contents of rocks. This is because Ca and Na preferentially combine with Si and Al to form Si-rich minerals, such as clinopyroxene and feldspar. This process will consume excessive SiO2, decreasing the SiO2activity. This may be the reason why zircon can be found in ultrabasic rocks, while baddeleyite can exist in some basic and alkaline rocks. The thermodynamic modeling can also reasonably explain the mutual transformation between zircon and baddeleyite in ultrabasic-basic rocks. Our results indicate that zircon can exist stably in mantle peridotite in a wide range of temperature-pressure conditions and its formation is related to melt/fluid metasomatism. That is, the presence of zircon in mantle peridotite is an important information carrier of crust-mantle interaction for deep material cycling.

Background: The CRISPR-Cas13 system is an RNA-guided RNA-targeting system and has been widely used in transcriptome engineering with potentially important clinical applications. However, it is still controversial whether Cas13 exhibits collateral activity in mammalian cells. Results: Here, we find that knocking down gene expression using RfxCas13d in the adult brain neurons caused death of mice, which may result from the collateral activity of RfxCas13d rather than the loss of target gene function or off-target effects. Mechanistically, we show that RfxCas13d exhibits collateral activity in mammalian cells, which is positively correlated with the abundance of target RNA. The collateral activity of RfxCas13d could cleave 28s rRNA into two fragments, leading to translation attenuation and activation of the ZAKα-JNK/p38-immediate early gene pathway. Conclusions: These findings provide new mechanistic insights into the collateral activity of RfxCas13d in mammalian cells and warn that the biosafety of the CRISPR-Cas13 system needs further evaluation before application to clinical treatments.

Psychological distress has long been suspected to influence cancer incidence and mortality. It remains largely unknown whether and how stress affects the efficacy of anticancer therapies. We observed that social defeat caused anxiety-like behaviors in mice and dampened therapeutic responses against carcinogen-induced neoplasias and transplantable tumors. Stress elevated plasma corticosterone and upregulated the expression of glucocorticoid-inducible factor Tsc22d3, which blocked type I interferon (IFN) responses in dendritic cell (DC) and IFN-γ+T cell activation. Similarly, close correlations were discovered among plasma cortisol levels, TSC22D3expression in circulating leukocytes and negative mood in patients with cancer. In murine models, exogenous glucocorticoid injection, or enforced expression of Tsc22d3in DC was sufficient to abolish therapeutic control of tumors. Administration of a glucocorticoid receptor antagonist or DC-specific Tsc22d3deletion reversed the negative impact of stress or glucocorticoid supplementation on therapeutic outcomes. Altogether, these results indicate that stress-induced glucocorticoid surge and Tsc22d3upregulation can subvert therapy-induced anticancer immunosurveillance. Stress reduces the effects of various cancer therapies, such as chemotherapy and immunotherapy, in mice; this is mediated, at least partially, through Tsc22d3 upregulation in tumor-infiltrating dendritic cells, which leads to immunosuppression.

The Cenozoic tectonic evolution of the Gangdese arc, formed by juvenile crustal growth during the Mesozoic, remains ambiguous. Here, we conducted a petrological, geochronological and geochemical study of Oligocene (32–24 Ma) granitoids with protolith ages of 57–49 and 27 Ma from the eastern Gangdese arc. Geochemically, these rocks are divided into three groups. Group I has high CaO and Sr, and low REE contents, representing plagioclase-rich cumulates. Group II contains relatively high K2O, Pb and REE, and low Na2O contents, and is crystallized from evolved magmas. Group III has relatively high Al2O3and Sr, and low MgO, Y, Yb, Cr and Ni concentrations, and is thickened lower-crust-derived adakitic rocks. The inherited zircon magmatic cores of these rocks have distinctly different [Formula] values (−9.88 to +8.50), whereas the magmatic rims have a narrow range of [Formula] values (−3.29 to +5.22). The Hf isotopic homogenization indicates intensive mixing of melts derived from the old and juvenile crustal materials. We concluded that the Cenozoic magmatic or sedimentary rocks were buried into the thickened lower crust and melted to generate the Oligocene granitoids, and that the Gangdese arc experienced lasting Paleogene crustal thickening and reworking.

The metamorphic evolution of the Eastern Himalayan Syntaxis (EHS) is of primary importance in understanding the tectonic framework of the India–Asia collision. However, the age of formation and exhumation of the high-pressure granulites from the EHS remains controversial. In this paper, we report the age of metamorphism of high-pressure (HP) granulite-facies paragneisses from the Namche Barwa Complex (NBC). These paragneisses consist of variable proportions of garnet, biotite, plagioclase, K-feldspar, quartz, rutile and ilmenite. Using phase equilibrium modelling of garnet growth combined with partitioning of rare earth elements (REEs) between zircon and garnet, we link multistage zircon growth to garnet growth to date the prograde stage to the interval 32.6–25.2 Ma, the pressure peak to c.25–24 Ma and the retrograde stage to the interval 23.5–13.1 Ma. Taking into account published ages from the literature, for the NBC we propose that the prograde to peak metamorphism persisted until c.25–24 Ma. This was followed by exhumation and melt crystallization during the interval 24–8 Ma, and cooling through the amphibolite facies after c.8 Ma.

High pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks play a key role for understanding the tectonic evolution of orogenic belts (Johnson, M.R.W. & Harley, S.L. 2012. Orogenesis: The Making of Mountains. Cambridge University Press, Cambridge). They have typically experienced complex changes during subduction and exhumation processes, arising from recrystallization, deformation, element redistribution, fluid–rock interactions and even partial melting, and may therefore carry a valuable record of evolving geodynamic systems in an orogenic belt. Until now, more than 20 UHP metamorphic belts, i.e. belts which contain rocks that experienced pressure–temperature (P–T) conditions exceeding the lower limit of the coesite stability field, have been identified all over the world (Carswell, D.A. & Compagnoni, R. 2003. Ultrahigh Pressure Metamorphism. Eotvos University Press, European Mineralogical Union, Notes in Mineralogy, Budapest; Liou, J.G., Ernst, W.G., Zhang, R.Y., Tsujimori, T. & Jahn, B.M. 2009. Ultrahigh-pressure minerals and metamorphic terranes – the view from China. Journal of Asian Earth Sciences,35, 199–231; Zheng, Y.F., Zhang, L.F., McClelland, W.C. & Cuthbert, S. 2012. Processes in continental collision zones: preface. Lithos, 136, 1–9). New and innovative studies from different geoscience disciplines have been invaluable in developing a better understanding of the geodynamic evolution of orogenic belts. This special issue contains 15 papers, most of which were presented as part of the session ‘HP–UHP metamorphism and tectonic evolution of orogenic belts’, held at the 35th International Geological Congress in Cape Town, South Africa during 27 August to 4 September, 2016.

Piezotronic effect is always mixed with piezoresistive effect when we investigate the electronic transport behaviors in the study of piezotronic devices. It is essential to separate the two effects, which is beneficial to the data analysis in actual applications. Here, we report a general method, alternative current (AC) impedance spectroscopy, to distinguish the piezotronic and piezoresistive effects in a strained piezo-Schottky junction. The study was performed on a copper (Cu) layer and F:SnO2( FTO) glass sandwiched zinc oxide (ZnO) nanowire arrays (Cu/ZnO/FTO). The AC spectra measured at various stress were simulated with appropriate equivalent circuits to reveal the possible change in the device. Our results showed the dominant role of piezotronic effect in the Cu/ZnO/FTO structure instead of piezoresistive effect which has been suspected previously. A capacitive effect of the sputtered ZnO seed layer was also observed. The origin of the capacitance was verified by the bias-independent impedance diagrams. This technique has provided a powerful tool to quantitative analysis on the inner changes of a strained piezotronic device, not only piezo-Schottky junction-based diodes, but also pn junction-based phototronics.

Inhalation of nebulized TP has received little attention in the past. Here, we intend to investigate the effect of nebulized inhaled TP on airway inflammation in a mouse model of asthma. 29 SPF BALB/c mice were divided into four groups: blank control (Blk, n = 5), normal saline (NS, n = 8), dexamethasone (Dex, n = 8), and TP (n = 8). During the process of sensitization, mice in the three intervention groups were treated with nebulized NS, an injection of Dex, and nebulized triptolide, respectively. Then bronchoalveolar lavage fluid (BALF), peripheral blood, and lung tissue were collected. Relevant cytokines, transcriptional factors, and CD4+Th17+ T cell proportions were assessed and compared. IL-6, IL-17, IL-23, and TGF-β1 demonstrated a significant difference between groups in the following order: Dex < TP < NS (P≤0.001), while IL-10 changed in the opposite direction (P<0.001). At the transcriptional level in lung tissue, the Ct value of IL-17 in the Dex group was significantly higher than in the NS and TP groups (P<0.001). Meanwhile, it was higher in the TP group than in the NS group (P<0.001). The Ct value of RORγt demonstrated a significant difference among three groups in the following order: Dex > TP > NS (P<0.001). An opposite trend of FoxP3 Ct value was revealed in the order: NS > TP > Dex. The proportion of CD4+Th17+ cells was 9.53 ± 2.74% in the NS group, 4.23 ± 2.26% in the Dex group, and 6.76 ± 2.99% in the TP group, which shows significant differences between the NS and Dex (P<0.001) or NS and TP groups (P<0.05). Inhalation of nebulized triptolide can play a role in suppressing airway inflammation with inflammatory cytokines and transcriptional factors reduced and CD4+Th17+ T cells dampened, also in a manner less than injected dexamethasone.

Dielectric/graphene/dielectric/metamaterials (MMs) structures are proposed to explore the properties of surface plasmon polaritons (SPPs). It is shown that p- and s-polarized SPPs can be observed in the terahertz frequency region in these structures. In addition, the existence regions, dispersion relations, and excitation of SPPs by attenuated total reflection technique can be controlled by changing graphene conductivity via the chemical doping or gate voltage, the parameters of MMs, and the component of structures. Tunable p- and s-polarized SPPs propagating along the graphene sheet and MMs may exhibit large propagation distances, low loss, and other advantages.

mRNA m6A modification is heavily involved in modulation of immune responses. However, its function in antiviral immunity is controversial, and how immune responses regulate m6A modification remains elusive. We here find TBK1, a key kinase of antiviral pathways, phosphorylates the core m6A methyltransferase METTL3 at serine 67. The phosphorylated METTL3 interacts with the translational complex, which is required for enhancing protein translation, thus facilitating antiviral responses. TBK1 also promotes METTL3 activation and m6A modification to stabilize IRF3 mRNA. Type I interferon (IFN) induction is severely impaired in METTL3-deficient cells. Mettl3fl/fl-lyz2-Cre mice are more susceptible to influenza A virus (IAV)-induced lethality than control mice. Consistently, Ythdf1−/−mice show higher mortality than wild-type mice due to decreased IRF3 expression and subsequently attenuated IFN production. Together, we demonstrate that innate signals activate METTL3 via TBK1, and METTL3-mediated m6A modification secures antiviral immunity by promoting mRNA stability and protein translation.

The Dabie-Sulu Triassic collisional orogen in eastern Asia was created by northward subduction of the Yangtze continental-crust capped plate beneath the Sino-Korean craton. Eclogites, garnet peridotites, and surrounding country rock gneisses and marbles were all subjected to in situ UHP metamorphism, as indicated by the presence of rare but widespread coesite inclusions in eclogitic minerals and in zircon crystals in the country rocks, as well as by virtually identical metamorphic ages of various UHP rock types. Metamorphic P-T estimates, combined with investigations of mineral exsolution textures and high-P polymorphs, indicate that recovered depths of continental subduction may have exceeded 200 km. Parageneses of mineral inclusions in zoned zircon domains combined with U-Pb ages delineate a well-constrained P-T-time path, suggesting exhumation rates of 5-10 km/Myr. A similar P-T-time trajectory has been established for the microdiamond-bearing Kokchetav Massif. Thus far, however, diamond inclusions have not been confirmed from coesite-bearing zircon domains of Dabie-Sulu UHP rocks despite numerous detailed studies. Oxygen isotopes of minerals from many outcrop samples and the Chinese Continental Scientific Drilling (CCSD) project main hole cores indicate that δ18O depletion took place in a volume of Proterozoic protoliths exceeding 100 000 km3along the northern edge of the Yangtze craton. Evidently, passive-margin sediments and bimodal igneous rocks that had formed during rifting and breakup of the supercontinent Rodinia were subjected to extensive meteoric waterrock interactions attending terminal Neoproterozoic Snowball Earth conditions. Such hydrothermal alteration volatilized and depleted C from the relatively oxidized protoliths, accounting for the rare occurrences of graphite and apparent lack of microdiamond in Dabie-Sulu UHP rocks.

Primary and exsolution fluid inclusions are recognized in omphacite of ultrahigh-pressure (UHP) eclogites from the main hole of the Chinese Continental Scientific Drilling Program, located in the southern Sulu orogenic belt. These oriented fluid inclusions occur as tubes, and coexist with exsolved quartz needles in the cores of host omphacite. Most complex primary fluid inclusions contain a gas bubble, a liquid phase, and one to several solids, such as quartz, halite, calcite, and opaque and unknown minerals, having compositions in the system of NaCl-CaCl2-CO2-H2O-SiO2 with possibly trace Fe and Mg; in contrast, simple fluid inclusions contain a gas, an aqueous liquid, and sometimes a calcite. We suggest that the complex fluid inclusions were trapped during the omphacite growth, whereas the simple aqueous inclusions and quartz needles exsolved from OH--rich supersilicic omphacite during early uplift of the UHP metamorphic rocks. Omphacite is one of the major fluid carriers during subduction of continental crust to mantle depths.

The crystal structure of the natural 33R moissanite, recovered as inclusions in chromitites from Luobusa harzburgite in Tibet, was determined from X-ray diffraction data collection by a Nonius CAD-4 four-circle diffractometer. The crystal is trigonal in symmetry with a space group of R3m. Identical to the synthetic specimen, the cell parameters are a= 3.076, c= 83.12 Å for the natural sample. Full-matrix least-squares refinement of the structure, including anisotropic displacement parameters, gave the final Rfactor of 4.80%.

The Chinese Continental Scientific Drilling (CCSD) Project in Donghai recovered more than 1000 m of eclogite and garnet peridotite cores for study. Examination of rocks from 100-2000 m of the main borehole has identified five major lithological types: (1) eclogite and garnet pyroxenite; (2) eclogitic gneiss; (3) garnet peridotite; (4) biotite (hornblende) two-feldspar gneiss; and (5) fault breccia and mylonite. The eclogite was further subdivided into two types: crustal eclogite and mantle-derived eclogite. Crustal eclogites are ubiquitous as layers of various thickness in gneissic rocks, and contain low-Prp (<40 mol%) garnet and omphacite. Mantle-derived eclogites are spatially associated with ultramafic cores composed mainly of garnet wehrlite, and have higher Prp-bearing (>40 mol%) garnet and low Jd-bearing clinopyroxene. Chemically, the crustal eclogites are relatively low in MgO and high in SiO2, but have high, variable contents of Al2O3 and rare-earth elements. Most crustal eclogites range in SiO2 content from 49 to 60 wt%, whereas mantle-derived eclogites are rich in MgO, and have SiO2 content less than 49 wt%. Garnet peridotites consist of olivine (Fo = 85-91), enstatite, Mg-rich garnet, and diopsidic clinopyroxene; Ti-clinohumite is also widespread. Mineral paragenesis indicates that the garnet peridotites together with other lithologies underwent in situ ultrahigh-P metamorphism (UHPM).Based on the differences in rock association, structural kinematics, and seismic characteristics, we have identified two different rock slices separated by a fault zone at 1600 m depth, where breccia and mylonite developed. Rutile eclogites are dominant in the upper slice, and phengite eclogites are layered with deformed tonalite and paragneiss in the lower slice. These UHPM rocks underwent variable retrograde metamorphism; eclogite is replaced by symplectite-bearing garnet amphibolite, and eclogitic gneiss is retrograded to biotite (hornblende) plagioclase gneiss. Late-stage crustal extension resulted in local cataclasis, forming tectonic breccia with the development of chlorite, calcite, hematite, and epidote under epidote amphibolite-to greenschist-facies conditions. Nearly 2000 m of recovered UHP core from the CCSD main hole reveals that voluminous crustal materials were subducted to mantle depths and rapidly returned to the surface. UHPM cores record subduction and exhumation processes of the continental crust and provide information for the study of continental subduction/collision and mantle dynamics.

The Pre-pilot Hole No. 1 of the Chinese Continental Scientific Drilling Project (CCSD-PPH1) in the southern Sulu terrane recovered a continuous core of eclogite, garnet peridotite, orthogneiss, paragneiss, and minor schist and quartzite. Geochemical characteristics indicate that the garnet peridotite was derived from depleted mantle; all other rock types are metamorphosed supracrustal rocks with continental affinities. The eclogite consists of garnet, omphacite, phengite, quartz (coesite), amphibole, rutile, and zircon; P-T estimates of peak metamorphism are 785-820°C and >2.7 to 3.7 GPa. The gneisses show common amphibolite-facies mineral assemblages consisting of plagioclase, K-feldspar, muscovite, and quartz, with minor garnet, epidote (or zoisite), and biotite; coesite inclusions in zircon indicate that the gneisses together with eclogites were subjected to an early UHP metamorphism prior to amphibolite-facies retrogression. The Garnet peridotites show porphyroblastic textures, and consist mainly of garnet, clinopyroxene, orthopyroxene, and olivine with minor phlogopite. Garnet and clinopyroxene porphyroblasts show significant compositional zoning. Applying relevant geothermobarometers, core compositions of the minerals indicate P-T conditions of 6.0-7.0 GPa and 1100-1200°C. For the rim, similar or slightly higher P-T conditions compared to the eclogites were obtained. We suggest that the former represent crystallization conditions of garnet peridotite in the upper mantle, whereas the latter reflect reequilibrium conditions during incorporation of mantle rocks into the subducted slab. We conclude that the garnet peridotite may have been derived from the mantle wedge above the subduction zone. If so, these mantle-derived rocks were sandwiched between continental-derived country rocks.

Rocks from the first pre-pilot hole of the Chinese Continental Scientific Drilling Project (CCSDPPH1, 432 m), located in the eastern part of the Dabie-Sulu ultrahigh-pressure (UHP) metamorphic belt, have been subjected to a coesite-eclogite-facies metamorphic event, followed by an amphibolite-facies overprint. Primary fluid inclusions occur in garnet, omphacite, and apatite from eclogite; in kyanite and in topaz from quartzite; and in garnet, epidote, and apatite from paragneiss. Secondary fluid inclusions are present in all lithologies. Fluid inclusions are absent from ultramafic rocks. Based on fluid compositions and textural criteria we distinguished: (1) low-salinity aqueouscarbonic inclusions in topaz from quartzite, which may have originated from a supracrustal protolith; (2) primary CaCl2-NaCl-rich brine inclusions in garnet and in omphacite from eclogite and in kyanite from quartzite, representing UHP metamorphic fluids; (3) high-salinity aqueous-carbonic inclusions in quartz from eclogite and quartzite, representing amphibolite-facies fluids; (4) aqueous fluids of low- and intermediate salinity trapped as primary inclusions in garnet, epidote (or allanite) and apatite from gneiss, or as secondary inclusions, representing amphibolite-facies and later retrograde fluids; (5) carbonic inclusions are distributed along transgranular fractures in quartz from quartzite, and probably represent the latest retrograde fluid. The diversity in fluid inclusion populations and compositions from different vertical depths suggests a closed fluid system without largescale fluid migration during UHP metamorphism. However, the common low- and medium-salinity inclusions in most rock types suggests that a water-dominated fluid from an external source infiltrated into the rock system during amphibolite-facies metamorphism, resulting in extensive retrogression of the UHP rocks.

Rope-driven mechanisms with the characteristics of high speed, low inertia, and high precision are widely utilized in numerous fields. Stiffness is an important indicator to illustrate the precision and compliance of the mechanism. However, realizing active stiffness control is difficult for the mechanisms due to the coupling of rope tension and controller stiffness. To solve the problem, a verification prototype, 2-DOF rope-driven parallel mechanism (RDPM), is designed and manufactured, and its mechanical model is established. And then the general stiffness model of the RDPM is derived. Meanwhile, the rope-hole friction is calculated based on the Stribeck model. An active stiffness control scheme considering the pose retention, vibration suppression, and friction compensation is proposed. According to the stiffness model and active stiffness control law, the linear motion stiffness of the RDPM is analyzed in detail. The conclusion shows the motion stiffness is linear with the controller stiffness and initial rope tension. Finally, the theoretical stiffness, simulation stiffness and experimental stiffness are calculated and compared by the co-simulation technique and physical prototype experiment. The error between experimental data and simulation data is within 10%, which verifies the stiffness model and active stiffness control scheme.

The Himalayan orogen, which formed due to collision of the Indian and Asian continents during the Early Tertiary, is a prime example of a large, hot collisional orogen. Despite decades of study, the duration of partial melting of migmatitic rocks exposed in the Himalayan orogenic core remains highly controversial. As such, we have performed detailed petrological and geochronological analyses of garnet amphibolite from the eastern Himalayan syntaxis in order to reveal the thermal conditions, tectonometamorphic mechanisms, and timing and duration of anatexis in metabasic rocks that form a major component of the thickened lower crust of the eastern Himalayan orogen. Phase equilibrium modeling and geothermobarometry show that the studied sample underwent high‐pressure granulite‐facies metamorphism and partial melting at 15−17 kbar and 805−840°C. Dehydration melting of amphibole during prograde metamorphism generated up to 20 vol. % partial melt with a granitic composition, which thus represents a potential source for Himalayan syn‐ to post‐orogenic crustal‐derived granites. Zircon U‐Pb geochronology shows that the garnet amphibolite witnessed a long‐lived anatectic and melt crystallization process lasting more than 30 Myr. Prolonged anatexis from ca. 40 to ca. 20 Ma predates initiation of the extrusion of Himalayan metamorphic core by up to 15 Myr, indicating that the thick and weak crust of the Himalayan‐Tibetan orogen must have remained stationary for this length of time, despite the ongoing continental collision. This study thus provides new insight into the tectonic evolution of hot orogens. We have conducted petrological and geochronological studies of garnet amphibolite from the eastern segment of Himalayan‐Tibetan orogen. Our results show that the rock experienced a prolonged high‐pressure and high‐temperature metamorphic and partial melting process from ca. 40 to ca. 20 Ma, indicating that the thickened, molten lower crust of the large hot orogen remained stationary for 15 Myr and then extruded toward the surface during ongoing continental collisional orogeny. Garnet amphibolite from the eastern Himalaya experienced high‐pressure prograde metamorphism and partial melting from ca. 40 to ca. 20 MaThe large volume (up to 20 vol. %) of granitic melt generated by dehydration melting of amphibole may have sourced the Himalayan granitesThe thickened, molten lower crust of the Himalayan‐Tibetan orogen remained stationary for 15 Myr during ongoing continental collision

During the course of searching for antiviral agents from Chinese medicinal herbs, we found that the supercritical fluid extract (SFE) of Centipeda minimapossessed good in vitroantiviral activity against influenza virus A/Puerto Rico/8/34 H1N1 (PR8). Bioassay-guided isolation and identification led to the isolation from this extract of seven pseudoguaianolides (1-7). These, as well as nine other sesquiterpene lactones (8-16) previously isolated from this herb were all tested for their anti-PR8 activity using both the cytopathogenic effect (CPE) reduction and cell counting kit 8 (CCK8) assays. As a result, eight pseudoguaianolides (1-8) possessing an α,β-unsaturated cyclopentenone moiety showed antiviral activity against PR8 to different extents. Of the active compounds, brevilin A (4) exhibited the strongest anti-PR8 activity, with an IC50value much lower than that of the positive control ribavirin. Mechanistic study revealed that brevilin A affected the intracellular replication of PR8 via downregulating the expression of viral M2 protein. All these results suggest the potential application of the pseudoguaianolides containing an α,β-unsaturated cyclopentenone moiety (e.g. brevilin A) in the treatment of influenza virus infection.