Search

Background The morbidity and mortality of sepsis are extremely high, which is a major problem plaguing human health. However, current drugs and measures for the prevention and treatment of sepsis have little effect. Sepsis-associated acute liver injury (SALI) is an independent risk factor for sepsis, which seriously affects the prognosis of sepsis. Studies have found that gut microbiota is closely related to SALI, and indole-3-propionic Acid (IPA) can activate Pregnane X receptor (PXR). However, the role of IPA and PXR in SALI has not been reported. Methods This study aimed to explore the association between IPA and SALI. The clinical data of SALI patients were collected and IPA level in feces was detected. The sepsis model was established in wild-type mice and PXR knockout mice to investigate the role of IPA and PXR signaling in SALI. Results We showed that the level of IPA in patients’ feces is closely related to SALI, and the level of IPA in feces has a good ability to identify and diagnose SALI. IPA pretreatment significantly attenuated septic injury and SALI in wild-type mice, but not found in knockout PXR gene mice. Conclusions IPA alleviates SALI by activating PXR, which reveals a new mechanism of SALI, and provides potentially effective drugs and targets for the prevention of SALI.

The research of unloading response characteristics of caverns with weak structure has important engineering value for the development and construction of underground space. In this paper, firstly, the cross fault cavity model is established based on particle flow code (PFC) software, considering different fault dip angles. The parallel bond model (PBM) is used in the cavern model and the smooth joint model (SJM) is used in the fault model. Then, the mechanical, acoustic emission (AE), energy response characteristics and failure modes of the cavern model with different fault angles are explored. The research result show that the fault angle has a great influence on the stress distribution and failure modes of surrounding rock.The existence of faults does not change the overall law of AE evolution curve, that is, the number of AE hits increases first and then decreases. However, the existence of faults changes the maximum number of AE hits and the duration of AE. When the cavern is unloaded, the strain energy of the model first decreases and then increases.

Three mesoporous silica materials (MCM-41, MSN and BMMs) possessing different morphologies but similar hexagonal arranged mesopores with almost the same pore size (2–3 nm) were functionalized by Zn and [1-(trimethoxysilyl)propyl-3-methylimidazolium] ionic liquid (ILs) via post-grafting treatment. The ILs grafted mesoporous silicas were then characterized by porosity, microscopy and SAXS techniques, and the successful loading of Zn and ILs, as well as the different distribution of functional groups in different supports were shown. Furthermore, the cycloaddition reaction of CO2 with epoxide was employed to evaluate the influences of the ILs distribution, which was proved to be caused mainly by varying morphologies of different supports. All the catalysts showed good catalytic activities. Interestingly, at low temperature, the inter particle supported ILs in BMMs had the highest catalytic efficiency, while the aggregation grafting ILs on MCM-41 present the lowest activity. However, the mesoporous silicas with ordered arranged nanopores present the superiority at higher temperature. The results highlight the crucial role played by the morphology of the supports.

Catalytic hydrodesulfurization (HDS) technique is widely used for clean gasoline production. However, traditional HDS catalyst (CoMo/γ-Al2O3) exhibits high hydrogenation performance of olefins (HYDO), resulting in the loss of gasoline octane number. To achieve high HDS/HYDO ratio, the key issue is to reduce the interaction between active metals and the support, therefore, in this research, the modified CoMo/γ-Al2O3 catalysts with various boron amounts were investigated under traditional or microwave heating. The effects of preparing methods as well as boron amounts on the active phase, acidic properties and HDS catalytic activities were examined. Results show that the modification, especially under microwave treatment, can significantly weaken the interaction between the active component and the support by enlarging the surface area and pore diameter, and reducing the acidity of the support. As a result, the stacking numbers of MoS2 slabs were obviously improved by the modification and microwave treatment, contributing to higher edge/ rim ratio, and resulting in higher HDS performance and selectivity to olefin.

Two new complexes based on pipemidic acid (HPPA) and Co2+/Cd2+ ions, [Co(PPA)2]·2H2O (1) and Cd(PPA)2 (2), have been synthesized and structurally characterized. Single-crystal X-ray diffraction analysis shows that complexes 1 and 2 exhibit similar structures containing two-fold meso-helices and 1D supramolecular channels. The interaction of calf-thymus (CT-DNA) with complexes 1 and 2 with was explored by UV spectrum, and competitive studies with ethidium bromide (EB) by fluorescence spectrum. Notably, these results indicate that complexes 1 and 2 possess the higher binding DNA affinity than free HPPA drugs, maybe attributed to the coordinated metal ions and the helical channels. And the resultant hypochromism suggests the tight binding of 1 and 2 with CT-DNA probably by the intercalative mode. Moreover, the relatively high Ksv value also indicates that 1 and 2 can bind to CT-DNA for the intercalative binding sites. Two new complexes based on HPPA were synthesized and structural description, and exhibit similar structures containing two-fold meso-helices. The result of the interaction with CT-DNA indicates that complexes can bind to the CT-DNA by the intercalative mode and possess the higher binding constant to CT-DNA than free HPPA drugs.

Treatment of Pb-Zn smelter wastewater via complexation-ultrafiltration (C-UF) was studied using copolymer of acrylic acid-maleic acid (PMA) as complexant. The complexing reaction kinetics of M (Cd(II), Pb(II) and Zn(II)) with PMA were examined for the first time and the pseudo-first-order model could be employed to simulate the reaction. The effects of the mass ratio of PMA to metal ions (P/M) and pH on the simultaneous removal of Cd(II), Zn(II) and Pb(II) via C-UF were investigated, and the optimized P/M and pH are 10 and 7.0, respectively. Furthermore, the shear stability of PMA-Cd, PMA-Zn and PMA-Pb complexes was investigated, and the corresponding critical shear rates (γc), the smallest shear rate at which the complexes begin to dissociate were 1.98×105, 1.81×104 and 1.38×105 s−1, respectively. The selective recovery of Cd(II), Zn(II) and Pb(II) from Pb-Zn Smelter wastewater as well as the regeneration of PMA were fulfilled by shear induced dissociation coupled with ultrafiltration (SID-UF) according to the difference of critical shear rates of PMA-M complexes, and the regenerated PMA showed almost the same complexation ability as the original.

The event-triggered sliding mode control problem is addressed for a class of networked switched systems subject to communication constraints. Not only the problem of network congestion, but also the problem of data collision is taken into account. In order to lighten network overloads and save bandwidth, an event-triggered scheme is utilized to decide whether a datum is transmitted or not and the Round-Robin protocol is employed to determine the priority of the actuator at a certain instant, which is a novel attempt to the sliding mode control problem for networked switched systems. Sufficient conditions are established such that the closed-loop system with sliding mode dynamics is exponentially stable. An event-based sliding mode control law is constructed under the Round-Robin protocol to drive the system trajectory into a bounded sliding vicinity around the sliding surface. Finally, a numerical example is given to demonstrate the effectiveness of the developed methods.

The grass Deschampsia cespitosa is a variable taxon out of which many varieties, subspecies and endemic species have been separated. In this paper, the variation in genome size (GS) and ploidy of this grass including several of its subspecies and two related species in Eurasia was investigated by flow cytometric (FCM) measurements. GS and ploidy data were also related to specific environments and reproduction mode. Ploidy levels found by FCM were confirmed by chromosome counts of diploid (2n = 28) and tetraploid (2n = 52) samples. Seminiferous (seed bearing) D. cespitosa was mainly diploid (GS between 3.754 and 5.438 pg/1C). GS variation in diploids showed a geographic pattern with a significant difference (H = 41,441, P D. cespitosa was found mostly in disturbed habitats in western and southern Europe, while tetraploids in Asia were registered in wet Arctic habitats. Genome size (1C between 8.3278 and 8.8603 pg) of the pseudoviviparous plants (spikelets produce plantlets asexually) of wet habitats in central and northern Europe indicated tetraploidy. A putative triploid (GS 6.6817 pg) was detected in Iceland. Summing up, we found a high variation in GS on the geographic scale with significant regional differences in diploid D. cespitosa. Among the tetraploids, the asexually reproducing plants were bound to specific habitats, while the seminiferous plants showed a habitat preference similar to the diploids.

This paper deals with the asynchronous H∞ control for discrete-time positive Markovian jump systems (PMJSs). In previous results about PMJSs, asynchronous behaviors are always overlooked and the designed controller is based on the synchronization between the system modes and controller modes. Sufficient conditions for stochastic stability are proposed by the use of Lyapunov-Krasovskii functional. The asynchronous controller is designed to ensure the closed-loop system stochastically stable with a prescribed H∞ performance index. All the conditions are given in linear matrix inequality framework. Finally, a pest’s age-structured population dynamic model is illustrated to show the validity of the present design.

The k-component edge connectivity $$c\lambda _{k}(G)$$ of a non-complete graph G is the minimum number of edges whose deletion results in a graph with at least k components. In this paper, we extend some results by Guo et al. (Appl Math Comput 334:401–406, 2018) by determining the component edge connectivity of the locally twisted cubes $$\mathrm{LTQ}_{n}$$ , i.e., $$c\lambda _{k+1}(\mathrm{LTQ}_{n})=kn-\frac{ex_{k}}{2}$$ for $$1\leqslant k\leqslant 2^{[\frac{n}{2}]}$$ , $$n\geqslant 7$$ , where $$ex_{k}=\sum _{i=0}^{s}t_{i}2^{t_{i}}+\sum _{i=0}^{s}2\cdot i\cdot 2^{t_{i}}$$ , and k is a positive integer with decomposition $$k=\sum _{i=0}^{s}2^{t_{i}}$$ such that $$t_{0}=\lfloor \mathrm{log}_{2}k\rfloor $$ and $$t_{i}=\lfloor \mathrm{log}_{2}(k-\sum _{r=0}^{i-1}2^{t_{r}})\rfloor $$ for $$i\geqslant 1$$ . As a by-product, we characterize the corresponding optimal solutions.

The purpose of the present study was to explore the antioxidant activity of organic extracts from Maillard reaction products (MRPs) of sea cucumber (Stichopus japonicus) gut hydrolysates (SCGHs). The SCGHs were obtained after treatment with neutrase, and they were then reacted with ribose at a mass ratio of 1:2, pH 8.0, and 95 °C for up to 12 h. The MRPs were extracted by methanol and ethanol. The methanol extracts of the MRPs had a higher UV absorbance, browning intensity, and fluorescence intensity than the crude MRPs. The scavenging capacities of methanol and ethanol extracts from MRPs in both 2′,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) assays increased significantly (p

The k-component connectivity $$c\kappa _{k}(G)$$ of a non-complete graph G is the minimum number of nodes whose deletion results in a graph with at least k components. A node subset S of G is called an optimal k-component cut if $$|S|=c\kappa _{k}(G)$$ and $$G-S$$ has exactly k components. In this paper, we determine the component connectivity of the locally twisted cube $$LTQ_{n}$$, i.e. $$c\kappa _{k+1}(LTQ_{n})=kn-k(k+1)/2+1$$ for $$1\le k\le n-1$$, $$n\ge 2$$, and characterize optimal k-component cuts of $$LTQ_{n}$$.

Scallop female gonad hydrolysates (SFGHs) were prepared by neutrase-hydrolysis. The characteristics and antioxidant activity of Maillard reaction products (MRPs) in SFGHs-sugar model systems were investigated. Results showed that antioxidant-producing MRPs could be prepared by heating SFGHs with ribose in a ratio of 1:2, with an initial pH value of 8.0, and a temperature of 95 °C for 6 h. Kinetics analysis indicated that elevated temperature (55–95 °C) and prolonged time (0–4 h) led to pH lowering of the MRPs, whereas an increase was observed for UV-absorbance, fluorescence intensity, and antioxidant activity. SFGHs-ribose MRPs exhibited excellent DPPH radical scavenging activity and reducing power with IC50 and AC0.5 values of 49.55 and 34.34 µg/mL, respectively. Additionally, SFGHs-ribose MRPs possessed significant protective ability of DNA damage at concentrations above 10 µg/mL. These results implied that the antioxidant activity of SFGHs could be enhanced via Maillard reaction with ribose, and the resulting MRPs might be used as food antioxidants.

Thermal flow-reversal oxidation is the main technology that can effectively reduce emissions of ventilation air methane. As the core component of coal mine ventilation oxidation devices, honeycomb ceramic oxidation beds play a decisive role in the functionality of these devices. The thermal fatigue properties of mullite ceramic, which is commonly used in oxidation beds, were tested in the present research. Then, the service life of the oxidation bed was predicted according to the intensity attenuation law and the thermal fatigue experimental data. The results of the fatigue experiment indicated that in general, the bending strength of mullite ceramics decreases as thermal shocks increase. At higher temperature differences, the bending strength decreased at higher rates. At the temperature differences between 600 and 800°C, the bending strength initially declined. Then, after reaching a certain value, it remained unchanged for a while before declining again. The calculation results via the proposed equation based on the intensity attenuation theory and the thermal fatigue experimental data indicate that the thermal fatigue life of an oxidation bed is about 1–8 months. The predicted result is consistent with actual working conditions.

The taxonomic status and phylogenetic placement of the monotypic genus Trichoneuron is studied using DNA sequences of three plastid-coding genes. Trichoneuron was originally assigned to Thelypteridaceae but has been considered to be a synonym of Lastreopsis in recent treatments. In this study, the proposed relationship of Trichoneuron to Lastreopsis was tested using a comprehensive taxa sampling of Dryopteridaceae. Our results strongly support the recognition of Trichoneuron as a distinct genus belonging to Dryopteridaceae. Trichoneuron does not group together with Lastreopsis. Instead the genus was found to be sister to the Neotropical genus Polystichopsis. This sister relationship is supported by the occurrence of long pluricellular hairs attached to the rachis of both genera. The morphological distinction of Trichoneuron from Lastreopsis is backed by the structure of the adaxial groove of rachis-costa junction and the hairs at abaxial side of leaf axes. The Polystichopsis–Trichoneuron clade was found to form the sister clade to an entirely Neotropical clade comprising Polybotrya and its relatives. The new subfamily Polybotryoideae is introduced based on the presented observations. In turn, the newly recovered sister relationship between Polystichopsis and Trichoneuron provides evidence for geographic disjunctions involving the Caribbean islands and the Indo–Burma biodiversity hotspot.

If the upstream boundary conditions are prescribed based on the incident wave only, the time-dependent numerical models cannot effectively simulate the wave field when the physical or spurious reflected waves become significant. This paper describes carefully an approach to specifying the incident wave boundary conditions combined with a set sponge layer to absorb the reflected waves towards the incident boundary. Incorporated into a time-dependent numerical model, whose governing equations are the Boussinesq-type ones, the effectiveness of the approach is studied in detail. The general boundary conditions, describing the down-wave boundary conditions are also generalized to the case of random waves. The numerical model is in detail examined. The test cases include both the normal one-dimensional incident regular or random waves and the two-dimensional oblique incident regular waves. The calculated results show that the present approach is effective on damping the reflected waves towards the incident wave boundary.

This paper focuses on the measurement of the permittivity of dimethyl sulfoxide (DMSO)–water (H2O) mixture solutions, at 2.45 GHz by using a resonant cavity perturbation method. A specific phenomenon was found, in that the imaginary part of the permittivity for the mixture solution was larger than the imaginary part for each component. Theoretical calculation indicated that the reason for that phenomenon was that the high frequency friction of the mixture was larger than that of each component. When comparing the theoretical results with the experimental data, it was found that the classical Debye equation must be modified in order to calculate the complex permittivity.

The main objective of this work is to measure the complex permittivity of ethanol + methanol liquid solutions over the full composition range at the temperatures 293, 303 and 313 K by the resonant cavity perturbation method. Dielectric parameters were derived using mixture formulae, and the values of excess permittivity and excess inverse relaxation time were determined using these parameters. By comparing the calculated results to the experiment values it was found that the classical Debye equation needs to be modified to calculate the complex permittivity.

In this paper, Fe3O4 nanoparticles coated with mesoporous silica were prepared successfully, noted as Fe3O4 at the mobile composition of matter No. 41 (MCM-41). Also, Fe3O4 at MCM-41 was grafted by both 3-aminopropyltriethoxysilane (APTS) and 3-chloropropyltriethoxysilane (CPS), noted as Fe3O4 at MCM-41/APTS and Fe3O4 at MCM-41/CPS. The compounds were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry, thermogravimetry and N2 adsorption/desorption. Then, the enzyme, porcine pancreas lipase (PPL), was immobilized onto these modified nanoparticles by covalent attachment, physical adsorption and cross-linking, noted as Fe3O4 at MCM-41/CPS-PPL, Fe3O4 at MCM-41-PPL and Fe3O4 at MCM-41/APTS-PPL, respectively. The results showed that Fe3O4 at MCM-41/CPS was the best nanomaterial for PPL immobilization, exhibiting enhanced immobilization efficiency (maximum 96%), maximum relative activity (up to 96%), high stability and reusability (83% 56 days and 86.7% ten cycles). Additionally, it offered some other advantages, such as easy recycling and reuse, complying with the trend of green chemistry. Therefore, Fe3O4 at MCM-41/CPS in combination with a relevant method can be proposed for commercial applications.