Search

Background Owing to high genetic diversities of tumor cells and low response rate of standard chemotherapy, patients with triple negative breast cancer (TNBC) have short progression-free survivals and poor outcomes, which need to explore an effective approach to improve therapeutic efficacy. Methods Novel gadolinium doped carbon dots (Gd@CDs) have been designed and prepared through hydrothermal method with 3,4-dihydroxyhydrocinnamic acid, 2,2′-(ethylenedioxy)bis(ethylamine) and gadolinium chloride. The synthesized nanostructures were characterized. Taking advantage of good biocompatibility of Gd@CDs, a nanoplatform based on Gd@CDs has been developed to co-deliver chemotherapy drug doxorubicin hydrochloride (Dox) and a near-infrared (NIR) photothermal agent, IR825 for magnetic resonance imaging (MRI) guided photothermal chemotherapy for TNBC. Results The as-synthesized Dox@IR825@Gd@CDs displayed favorable MRI ability in vivo. Upon NIR laser irradiation, Dox@IR825@Gd@CDs could convert the NIR light to heat and efficiently inhibit tumor growth through photothermal chemotherapy in vitro and in vivo. Additionally, the impact of photothermal chemotherapy on the murine motor coordination was assessed by rotarod test. Dox@IR825@Gd@CDs presented low toxicity and high photothermal chemotherapy efficiency. Conclusion A noble theranostic nanoplatform (Dox@IR825@Gd@CDs) was developed that could be tailored to achieve loading of Dox and IR825, intracellular delivery, favorable MRI, excellent combination therapy with photothermal therapy and chemotherapy to enhance therapeutic effect against TNBC cells. This study will provide a promising strategy for the development of Gd-based nanomaterials for MRI and combinational therapy for TNBC. Graphic abstract

Graphene has presented promising features for application in lithium ion batteries(LIBs) due to its superior electronic conductivity and high surface area. It has been successfully used for modifying cathode materials to meet the increasing demand for LIBs with longer cycle life. However, the improving effect of graphene on cycling stability is still unclear, which restricts its further application in LIBs. Herein, graphene coated hollow sphere-like structure LiNi0.5Mn1.5O4(LNMO) was designed and the improvement mechanism of graphene coating on LNMO's cycling stability was investigated. The results show that graphene coating not only contributes to suppress structural deformation from mechanistic reaction and extend solid-solution reaction, but also helps protect electrode from corrosion by the products from electrolyte decomposition and suppress the generation of surface defects, especially at high temperature. Owing to graphene coating, graphene coated LNMO can deliver a discharge capacity of 91 mAh g−1 with high capacity retention of 82.5% after 1000 cycles under 20C and 83.8 mAh g−1 with 94.5% capacity retention after 100 cycles under 2C at 55 °C. This work deeply explores the effect of graphene coating on cycling stability from crystal stability and surface stability, which will help a wider application of graphene in energy storage field.

The hollow microspherical structure cathode materials of bimetallic disulfide CoxNi1-xS2 (x varied from 0.1 to 0.5) for lithium thermal battery were synthesized by hydrothermal method. The structure, morphology, and composition of the hollow CoxNi1-xS2 were evaluated by field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The thermal stability was assessed by differential thermal analyzer (DTA). The thermal battery fabricated with CoxNi1-xS2 as cathode active material and LiB as anode exhibits the good electrochemical performance at 450 °C. Especially when x = 0.1, the initial discharge voltage reached 2.037 V, and specific capacity was 297.4 mA h g−1 at cut-off voltage of 1.5 V during constant current discharge. The bimetal disulfide material also presented advantages of reducing the internal resistance of the single cell.

Considering the rhizosphere microbes easily affected by the environmental factors, we formulate a three-dimensional diffusion model of the rhizosphere microbes with the impulsive feedback control to describe the complex degradation and movement by introducing beneficial microbes into the plant rhizosphere. The sufficient conditions for existence of the order-1 periodic solution are obtained by using the geometrical theory of the impulsive semi-dynamical system. We show the impulsive control system tends to an order-1 periodic solution if the control measures are achieved. Furthermore, we investigate the stability of the order-1 periodic solution by means of a novel method introduced in the literature [Y. Ye, The Theory of the Limit Cycle, Shanghai Science and Technology Press, 1984.]. Finally, mathematical results are justified by some numerical simulations.

Stepwise modification of ovatodiolide revealed a prodrug, NMP-diepoxyovatodiolide, which can provide sustained release of an active compound, substantial metabolic stability and a unique accumulation profile in the liver. Besides, NMP-diepoxyovatodiolide demonstrated therapeutic benefits in an acute autoimmune hepatitis mouse model and a broad safety window. Therefore, NMP-diepoxyovatodiolide is a very promising candidate for further development of liver-related drugs.

The combined effects of cinnamaldehyde (CA) and ultrahigh pressure (UP) treatment on the flavor of olive flounder (Paralichthys olivaceus) fillets during storage at 4 °C for 20 days were investigated. Changes in total viable count, trimethylamine, ATP-related compounds, free amino acids, TCA-soluble peptides, electronic nose (E-nose) analysis and sensory quality were measured. The results indicated that CA and UP treatment, especially CA combined with UP, significantly reduced undesirable flavor compounds including inosine, hypoxanthine, TMA, and bitter amino acids, and accumulated pleasant flavor compounds such as inosine monophosphate and umami-related amino acids. In addition, the combination of CA and UP was shown to be more effective for retarding protein degradation and microbial growth than CA or UP treatment alone. In accordance with the results of E-nose analysis and sensory evaluation, CA combined with UP treatment had great potential for improving the flavor quality of refrigerated flounder fillets and extending their storage life.

Rhubarb anthraquinone glycosides (RAGs) have been proven to have significant therapeutic effects on ischemic stroke, and this effect may be related to the microbiome-gut-brain axis. In this study, an HPLC-FLD method was established to measure brain-gut neurotransmitters of rats with cerebral ischemia-reperfusion injury (CIRI), to explore whether the mechanism of RAGs against CIRI is related to the microbiome-gut-brain axis. A Shimadzu ODS-3 C18 column was used for chromatographic separation, and 5-hydroxytryptamine (5-HT), 5-hydroxy indole acetic acid (5-HIAA), glutamic acid (Glu), aspartic acid (Asp), and γ-aminobutyric acid (GABA) were determined simultaneously. The results showed that there is an excellent linear relationship (R2 ≥ 0.9990) and a high separation degree in the HPLC-FLD method. Whereas the contents of Asp and Glu in the brain and colon increased (p < 0.05), the contents of 5-HT, 5-HIAA, and GABA in the brain and colon decreased (p < 0.05) after CIRI. RAGs could effectively reduce the contents of Asp and Glu (p < 0.05), and increase the contents of 5-HT, 5-HIAA, and GABA in the brain and colon (p < 0.05). Combined with the previous experimental results, we can speculate that RAGs can regulate intestinal flora disorder caused by CIRI, and then regulate the imbalance between the release and decomposition of neurotransmitters caused by intestinal flora disorder.

Jahanyne, a lipopeptide with a unique terminal alkynyl and OEP (2-(1-oxo-ethyl)-pyrrolidine) moiety, exhibits anticancer activity. We synthesized jahanyne and analogs modified at the OEP moiety, employing an α-fluoromethyl ketone (FMK) strategy. Preliminary bioassays indicated that compound 1b (FMK−jahanyne) exhibited decreased activities to varying degrees against most of the cancer cells tested, whereas the introduction of a fluorine atom to the α-position of a hydroxyl group (2b) enhanced activities against all lung cancer cells. Moreover, jahanyne and 2b could induce G0/G1 cell cycle arrest in a concentration-dependent manner.

Modeling the wetland plant–nutrient interaction is significant for elucidating the complex mechanisms of the nutrient absorption. In this paper, the effect of pollutant dispersal and impulsive input on the growth of wetland plant is presented. By using the theory of impulsive differential equations, we obtain that the wetland plant-eradication periodic solution is globally asymptotically stable if some conditions are satisfied. In addition, the permanent conditions are given by means of the comparison theorem of impulsive differential equations. Finally, numerical simulations are given to justify our results.

Saccharina japonica is one of the most important marine crops in China, Japan and Korea. Candidate genes associated with blade length and blade width have not yet been reported. Here, based on SLAF-seq, the 7627 resulting SNP loci were selected for genetic linkage mapping to 31 linkage groups with an average spacing of 0.69 cM, and QTL analyses were performed to map the blade length and blade width phenotypes of S. japonica. In total, 12 QTLs contributing to blade length and 10 to width were detected. Some QTL intervals were detected for both blade length and width. Additive alleles for increasing blade length and width in S. japonica came from both parents. After the QTL interval regions were comparatively mapped to the current reference genome of S. japonica (MEHQ00000000), 14 Tic20 (translocon on the inner envelope membrane of chloroplast) genes and three peptidase genes were identified. RT-qPCR analysis showed that the transcription levels of four Tic20 genes were different not only in the two parent sporophytes but also at different cultivation times within one parent. The SNP markers closely associated with blade length and width could be used to improve the selection efficiency of S. japonica breeding.

Acrylonitrile–butadiene rubber (NBR)/anhydrous copper sulfate (CuSO4) composites were prepared by coordination cross-linking. CuSO4 particles of different sizes are obtained by ball milling in acetone. During heat pressing at 190 °C, a strong cross-linking reaction occurred, which resulted from coordination between cupric ions and nitrile groups. Results showed that the mean size of CuSO4 particles decreased from 7.1 to 0.4 μm after ball milling. Accordingly, the number of coordination cross-linking points increased remarkably, which resulted in an increase in the glass transition temperature and equilibrium torque of the composites. Two models were employed to discuss the cross-link density and demonstrated that both CuSO4 particles and cupric ions contributed to the improvement of cross-linking points. It was noteworthy that this composite exhibited high strength and toughness, with 73.5 MPa tensile strength and 423.7% elongation at break. Moreover, a unique stretching phenomenon, including the features of both rubber and plastic, was observed and explained in detail.

Circulating tumour cells isolated from the peripheral blood of patients have the advantage of being non-invasive. The aim of this study was to develop an effective method for detecting pancreatic cancer micrometastasis from peripheral blood and explore the clinical application value of the separation of circulating pancreatic cancer cells using epithelial cell adhesion molecule (EpCAM) lipid magnetic spheres (ELMS) and plastin monoclonal antibody for identification. The pancreatic cancer PANC-1 cells were respectively added to phosphate-buffered saline (PBS) and fresh blood provided by healthy volunteers to detect cell recovery using ELMS. Moreover, trials were conducted using nude mice with tumour and samples from patients with pancreatic cancer to evaluate the effect of CTC isolation and identification. The prepared ELMS captured PANC-1 cells from blood with high efficiency, which was similar to the efficiency obtained with nude mice with tumour and the samples from patients with pancreatic cancer, in agreement with the clinical test results. This study is based on the high efficiency of the EpCAM magnetic nanolipid sphere separation system capturing CTC of pancreatic cancer, which provides a strong support for investigating pancreatic cancer, in terms of its early diagnosis, preoperative and post-operative analysis and analysing the treatment effects.

The recycling and self-healing functions of commercial rubber are of great significance in the field of sustainable materials. So far, manufacturing such rubber with excellent strength and toughness was still a huge challenge. Herein, the multi-coordination crosslink networks were designed to achieve this goal. First, the nitrile-butadiene rubber (NBR) was modified through 3,6-di(2-pyridyl)-1,2,4,5-tetrazine (DPT) click reaction to introduce the second ligand group. Next, the blend of modified NBR and metal salt (including ZnCl2 and CoCl2) was hot-pressed to form the metal-nitrile and metal-pyridine (nitrogen-containing heterocyclic groups) coordination bonds. The designed composite had ultra-high mechanical strength and toughness at the same time. Compared with the NBR/ZnCl2 composite, the tensile strength of NBR-DPT4-Zn10 composite with multi- coordination bonds was improved by 7.5-fold (from 5.5 MPa to 46.82 MPa), and the corresponding fracture energy was improved by 142% (from 26.2 MJ m−3 to 63.5 MJ m−3). At the same time, the high recyclable and heat-healing efficiency were obtained. These achievements are expected to develop commercial rubber’s recyclability and high mechanical properties.

Damping rubber, which is a blend of chlorinated isobutylene isoprene rubber (CIIR) and micromolecule resins (petroleum resins or rosin resins), was impregnated onto Wrap Knitted Spacer Fabric (WKSF) through solution method in order to produce damping rubber/WKSF composites. CIIR-grafted–(maleic anhydride) (abbreviated as CIIR-g-MAH) was synthesized and used as a novel compatibilizer for damping rubber/WKSF composites. The loss tangent factor (tan δ) values decreased and the tan δ peak moved to a lower temperature after WKSF was added. The tensile strength of the damping rubber was improved significantly with the skeleton structure of WKSF. The addition of CIIR-g-MAH increased the tensile strength further. Interfacial shear strength showed strong interactive interface between the matrix and the polyethylene terephthalate (PET) fiber of WKSF after the addition of CIIR-g-MAH. Scanning electron microscopy showed the morphology of the fracture surface and the interfacial compatibilization mechanism was investigated. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers

Crosslinked ultra-high-molecular-weight polyethylene (UHMWPE) with excellent shape memory properties was prepared from the silane-grafted UHMWPE mixed with water-carrying agent by compression molding. The alkoxysilane hydrolyzation and condensation reaction of the silane-grafted UHMWPE allowed for the generation of Si–O–Si chemical crosslinking points between the polymeric chains. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results confirmed that silane has been grafted on UHMWPE chains successfully. The resulting crosslinked products were characterized using dynamic mechanical analysis, gel measurement, impact test, tensile test, thermogravimetric analysis and shape memory bending test to obtain insight into the relationship between the structure and the properties. By controlling the content of water-carrying agent, the average molecular weights between crosslinking points (M c) reduced from 29,530 to 9540 g/mol. The decomposition temperature (T d) value increases from 467.7 for virgin resin to 491.5 °C for the crosslinked product with 91.64% gel ratio. The crosslinked materials showed much better shape memory effect than pure UHMWPE; the shape recovery ratio (R ν ) value of silane-induced crosslinked UHMWPE with 1.0 phr water-carrying agent reaches above 98.0% under multiple deformation recovery cycle. Therefore, the silane-induced crosslinking UHMWPE has a great potential in the shape memory material applications.

Ceramifiable flame-retardant silicone rubber composites were prepared by silicone rubber (SR) as the base polymer, and ammonium polyphosphate, calcium carbonate, sericite mica, and glass frits were utilized as additives. The flammability and thermal stability properties of ceramifying silicone rubber composites were studied by the limiting oxygen index (LOI), microscale combustion calorimetry (MCC), and thermogravimetric analysis (TG). The ceramic residues formed at various temperatures were studied by mechanical testing, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results indicated that the ceramifying silicone rubber achieved a LOI value of 31.2% and the flexural strength of ceramic residues formed at 1000 °C was 19.7 MPa. Moreover, the MCC results demonstrated that the heat release rate and total release rate of the composites were reduced significantly compared to the corresponding value of neat SR. The TG showed that the residue of composites was approximately 61.5% at 700 °C, as significantly higher than that the residue of neat SR. The XRD results demonstrated that fluoroapatite and Ca2SiO4 crystals were produced in the ceramic residue at high temperatures. The SEM analysis depicted that the number of holes was reduced and a dense structure was formed as the sintering temperature increased, leading to the excellent mechanical properties of formed ceramics at high temperatures.

Acrylonitrile–butadiene–styrene (ABS) composites filled with anhydrous copper sulfate (CuSO4) particles were prepared by planetary ball mill. The ball milling process can provide CuSO4 particles of small sizes for homogeneous particle distribution in a matrix. To directly enhance the interaction between the two ingredients, a coordination reaction was generated by heat press at 180 °C. Fourier transform infrared, electron spin resonance, Ultraviolet–visible, and X-ray photoelectron spectroscopy were employed to investigate the coordination reaction. The results showed that a coordination reaction happened between nitrile groups (–CN) of ABS and copper ions (Cu2+) of CuSO4. The loss factor of dynamic mechanical analysis indicated the decrease of intermolecular friction due to a strong interaction between the matrix and the particles. The homogeneously dispersed, micro-sized CuSO4 particles were observed by scanning electron microscope. The interface was indistinguishable under the microscope indicating a well-bonded surface and good compatibility. In addition, dissolution behavior showed that the solvent resistance of the composites was significantly improved.

Ceramifiable composites based on silicone rubber (SR) filled with mica powder, glass dust (GD) and short glass fiber (SGF) were successfully prepared for high-temperature applications. The effect of the GD/SGF phr ratio in the fluxing agents on the ceramifiable and mechanical properties of the silicone rubber composites was studied. The results demonstrated that the composites showed excellent properties when the ratio of GD/SGF was 1 : 1 and the corresponding tensile strength was 6.5 MPa. The elongation at break of the composites reached 245.4% and the flexural strength of sintered samples produced at 1000 °C was 16.2 MPa. Thermogravimetric analysis (TGA) results indicated that the char residue was 57.5% at 700 °C, which was much higher than the virgin SR residue. The ceramization process at different sintering temperatures was consequently studied through infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The linear shrinkage and flexural strength of sintered samples increased with increasing sintering temperature from 600 to 1000 °C. The FTIR and XRD tests indicated that the fluorophlogopite mica structure was destroyed and a new cristobalite crystalline phase was formed at elevated temperature. The SEM revealed that a coherent and dense microstructure of sintered samples was formed with increased temperatures, which contributed to the flexural strength improvement.

Background Gout is the second most common metabolic disease affecting human health. The disease of gout is closely related to the level of uric acid, which is the end-product of human purine metabolism. Moreover, food is the main way of external ingestion of purine. Method A simple and time-saving method was developed to extract purines like adenine, hypoxanthine, guanine, and xanthine from marine fish by single factor design combined with Box–Behnken. The contents of these purines in the edible parts and internal organs of marine fish, as well as Scophthalmus maximus, were determined by high-performance liquid chromatography to investigate the relationship between the boiling process and purine content. Result The mixed-acid method was chosen for the extraction of purine bases and the extraction conditions were as follows: mixture acid 90.00% TFA/80.00% FA (v/v, 1:1); hydrolysis temperature 90.00 °C; time 10.00 min; liquid-to-solid ratio 30:1. The total purine content of the edible parts (eyes, dorsal muscles, abdominal muscles, and skin) was the highest in Scophthalmus maximus, followed by sphyraena, Sardinella, Trichiurus lepturus, Scomberomorus niphonius, Pleuronectiformes, Sea catfish, Anguillidae, and Rajiformes. Moreover, boiling significantly reduced the purine content in the marine fish because of the transfer of the purines to the cooking liquid during boiling. Scophthalmus maximus, Sphyraena, and Sardinella were regard as high-purine marine fish, which we should eat less. We also confirmed that boiling significantly transferred purine bases from fish to cooking liquid. Thus, boiling could reduce the purine content of fish, thereby reducing the risk of hyperuricemia and gout.

As an important ecosystem, alpine meadow in China has been degraded severely over the past few decades. In order to restore degraded alpine meadows efficiently, the underlying causes of alpine meadow degradation should be identified and the efficiency of restoration strategies should be evaluated. For this purpose, a mathematical modeling exercise is carried out in this paper. Our mathematical analysis shows that the increasing of raptor mortality and the decreasing of livestock mortality (or the increasing of the rate at which livestock increases by consuming forage grass) are the major causes of alpine meadow degradation. We find that controlling the amount of livestock according to the grass yield or ecological migration, together with protecting raptor, is an effective strategy to restore degraded alpine meadows; while meliorating vegetation and controlling rodent population with rodenticide are conducive to restoring degraded alpine meadows. Our analysis also suggests that providing supplementary food to livestock and building greenhouse shelters to protect livestock in winter may contribute to alpine meadow degradation.

In this paper, a tumour-immune model with pulsed treatment of different frequency is proposed. The globally attractive conditions of the tumour-free periodic solution are presented in views of the comparison theorem for impulsive differential equations. Furthermore, the effect of period, dosage and times of drug delivery on the critical threshold is addressed by means of computer simulation, which indicates that there exists an optimal frequency of chemotherapeutic application. In addition, a tumour-immune model with fixed-time pulsed of immunotherapy and state feedback impulsive chemotherapy is given to keep the normal cells above and toxicity below the acceptable levels. Some numerical results are also provided to investigate the effect of the initial densities, predetermined threshold, drug dose and impulsive period on the dynamical behavior of hybrid impulsive system.

Carbon black (CB) was encapsulated by the sodium lignosulphonate via the strong π–π* interaction force of aromatic ring in the planetary ball milling instrument. The use of new surfactant and ball milling instrument met the requirements about the low-cost standard and provided an important sense to industrialization in comparison with the old surfactant, the poly(sodium 4-styrenesulfonate). The successful encapsulation was confirmed by Raman spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and thermal gravimetric analysis. Encapsulation ratio of the modified CB increased to 15.9% when CB was prepared at longer milling time and with agate balls in different size. The morphology and dispersibility of samples studied by transmission electron microscope, sedimentation experiment and ultraviolet–visible spectroscopy showed that the modified CB dispersed stably in the deionized water. The average diameter and absolute value of zeta potential of the modified CB decreased and increased compared with those of CB, respectively, which confirmed further that sodium lignosulphonate encapsulated on the surface of CB make CB disperse better. In addition, the average diameter and zeta potential of the samples were affected by ball milling conditions. The modified CB prepared at longer milling time and with different sizes of agate balls had better dispersibility than the ones prepared at shorter milling time and with same size of agate balls. Copyright © 2016 John Wiley & Sons, Ltd.

Polytetrafluoroethylene (PTFE)/carbon black (CB) microporous membranes with excellent properties were successfully prepared via heterocoagulation process and mechanical stretching method. Heterocoagulation was achieved using PTFE emulsion with 26% solid content, an intermediate product of the commercial PTFE dispersions with 60% solid content, and CB dispersions to prepare PTFE/CB composite particles by mechanical stirring, which is the unique content in this article. Furthermore, in order to obtain uniform distribution of CB particles within the membrane matrix as well as improve color uniformity and mechanical strength of the microporous membranes, CB was pretreated by a titanate coupling agent (NDZ-201). The PTFE/CB composite particles were then used to prepare the PTFE/CB microporous membranes via mechanical stretching operation. Several important properties of the prepared PTFE/CB microporous membranes, such as tensile strength, porosity, contact angles, morphology, and dynamic mechanical properties, were investigated. Results showed that the fabricated PTFE/CB microporous membranes possessed color uniformity, high tensile strength, and high hydrophobicity.

Dual coordinated cross link networks were designed in epoxidized butadiene-acrylonitrile rubber (NBR)/CuSO4 composites to make commercial NBR become advanced soft materials. First, NBR was modified through organic peroxy acid method to produce epoxidized butadiene-acrylonitrile rubber (ENBR). Next, CuSO4 was introduced in bulk to form strong Cu2+-nitrile coordination bonds acting as strong cross link points and Cu2+-epoxy bonds acting as weak cross link points. XPS analysis, FT-IR spectra and rheological curves proved the dual coordination bonds. Curing rheology curves, crosslinking density and thermal properties effectively demonstrated the formation of related dual cross link networks. The ENBR/CuSO4 composites exhibited excellent mechanical properties due to the synergistic effect of strong and weak metal-ligand coordination networks. During stretching, the weak coordination bonds acted as sacrificial bonds which could dissipate energy, while the strong coordination bonds sustained the network and imparted the elasticity. Under the combined functions of dual coordination bonds, the modulus, tensile strength, and toughness of ENBR/CuSO4 composites could be improved and tuned by controlling the structure parameter of coordination networks such as epoxidation degree and content of CuSO4.

Now, the urbanization process of China is accelerating. Urban land price is of great interest for the government to make reasonable policies and keep the healthy development of land market. Based on the data source of dynamic monitoring system and the statistical yearbook of Chengdu city, we identifies the related factors influencing the comprehensive land price of Chengdu. Firstly, we identified the nine strongly correlative factors of land price of Chengdu city. Secondly, we derived the land price for prediction. Thirdly, we compared the predicted land price with the real land price in the period of 2014–2015. Finally, the comprehensive land price of Chengdu in the period of 2017–2018 was forecasted with random forests and neural network, respectively. According to the results, we found that the error of the random forests is much smaller than that of neural network. Thus, we utilized random forests to predict the comprehensive land price of Chengdu in the period of 2017–2018. Our results showed that the comprehensive land price of Chengdu in the next two years would be stable and rises slightly.

Flake silver powder with controllable particle size and specific surface area was prepared using planetary ball mill by varying milling parameters including milling time, revolution speed, and the weight ratio of balls to powder (BRP). As-prepared flake silver powder was characterized by laser particle analyzer, scanning electron microscope, X-ray diffraction (XRD) and thermal gravity analysis (TGA). Results showed that the flake silver powder with the mean size of 4.0 μm and the specific area of 0.64 m2 g−1 can be obtained when the revolution speed was 350 r/min, the BRP was 15:1, the grinding time was approximately 30 h and a mixture of 1.5 % stearic acid and 0.5 % oleic acid was used as grinding aids. XRD patterns confirmed that the milled powder was pure silver, indicating there were no silver oxide and the alleged impurities caused by oxidation reaction and friction and wear with the increase of BRP value respectively under the present experimental conditions. TGA showed that the obtained powder was easy to wash and without absorption, which is very important and beneficial to the conductivity of the electrodes.

The thermal conductivities of polycarbonate (PC) composites filled with carbon fillers, including carbon black (CB), multi-walled carbon nanotubes (MWCNTs) and exfoliated graphite (EG), were studied. EG filler provided substantially greater thermal conductivity enhancement when embedded into PC matrix compared with CB and MWCNTs at the same loading. To further improve the thermal conductivity of PC composite, a hybrid EG/MWCNTs filler was used. When the hybrid filler loading was 10 mass%, the radio of EG: MWCNTs was 9:1, and the thermal conductivity of PC composite showed a maximum value of 1.19 W m−1 K−1 higher than that filled with EG or MWCNTs alone, indicating that the combination of EG and MWCNTs demonstrated a synergistic effect for the thermal conductivity enhancement of PC. EG/MWCNTs/PC composite with thermal conductivity >5 W m−1 K−1 was fabricated when the filler content was 40 mass%, which would widen its field of applications in electrons, LED lamps and aerospace.

Nanosized Sb doped SnO2 (ATO) particles were successfully synthesized. Electrically conducting rubbery composites based on epichlorohydrin rubber (ECO) and two kinds of conductive fillers (SnO2 and ATO) were prepared by a conventional blending method. The morphology, structure and electrical conductivity of ECO/SnO2 and ECO/ATO composites were investigated. Results showed that SnO2 and ATO had great influence on the structure of ECO composite. Besides, the addition of oxide particles enhanced its electrical conductivity significantly. The electrical conductivity of ECO/ATO composite appeared an obvious threshold value with the variation of the loading amount of ATO fillers, whereas the resistivity of ECO filled with SnO2 decreased monotonically with the increasing SnO2. The temperature dependence of resistivity indicated that the ECO/SnO2 and ECO/ATO composites exhibited a negative temperature coefficient (NTC) effect. Scanning electron microscopy (SEM) was used to investigate the morphological states of oxide fillers in ECO matrix, and specifically continuous networks were observed. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Nannocystin A is a potent antiproliferative cyclodepsipeptide targeting eukaryotic translation elongation factor 1α. To elucidate the binding role of its (2R,3S)-epoxide, we designed and synthesized a focused library of 10 nannocystin analogues. Variable temperature NMR experiments demonstrated the importance of the (2R,3S)-epoxide in controlling the macrocyclic conformation. Biological evaluation of these compounds against three typical cancer cell lines established a clear structure-activity relationship at the epoxide region, which was rationalized by comparing the superimposed conformations of different nannocystin analogues and in silico docking analysis. Our results showed that the (2R,3S)-epoxide of nannocystin A is mainly responsible for controlling the macrocyclic conformation, rather than binding directly to the target.

Saccharina japonica is a commercially and ecologically important seaweed and is an excellent system for understanding the effects of domestication on marine crops. In this study, we used 19 selected simple sequence repeat (SSR) markers to investigate the influence of domestication on the genetic diversity and structure of S. japonica populations. Wild kelp populations exhibited higher genetic diversity than cultivated populations based on total NA, HE, HO, NP and AR. Discriminant analysis of principal components (DAPC), a neighbour-joining (NJ) tree and STRUCTURE analyses indicated that S. japonica populations could be divided into two groups (a cultivated/introduced group and a wild indigenous group) with significant genetic differentiation (P S. japonica has not resulted in any serious genetic disturbance of wild introduced S. japonica populations. An understanding of the genetic diversity and genetic structure of domesticated S. japonica will be necessary for further genetic improvement and effective use of germplasm.

In this paper, a mathematical model of conversion from a drug-sensitivity strain to a drug-resistant strain is given to investigate how antibiotic usage may be optimized to preserve or restore antibiotic effectiveness. This novel theoretical framework could result in an optimal criterion on how to reduce the drug resistance to a reasonable range by using the antibiotic dressing strategy. The sufficient conditions of existence of order-1 periodic solution are obtained in view of the geometrical theory of the semi-continuous dynamical system and the qualitative properties of the corresponding continuous system. The stability of the order-1 periodic solution is proved by means of [H. J. Guo, L. S. Chen and X. Y. Song, Qualitative analysis of impulsive state feedback control to an algae-fish system with bistable property, Appl. Math. Comput. 271 (2015) 905–922]. Finally, our results are confirmed by means of numerical simulations.

Many studies show that software reliability growth models (SRGMs) have good performance when considering the randomness of the field environments. In this paper, we propose a new software reliability model incorporating S-shaped testing coverage with the randomness of the field environments. Parameters of the new model are estimated by means of the least square estimation (LSE) method. Comparison of this model with other existing NHPP models has also been presented. Five goodness-of-fit criteria are used to compare the performance of the proposed model with several existing NHPP SRGMs based on one actual failure data set collected from software application. The results show that the proposed model can fit significantly better than all other existing NHPP models.

International audience; Two melting peaks are generally observed in a heating scan for isothermally crystallized poly(lactic acid) (PLA)/carbon black (CB) and PLA/modified carbon black (MCB) composites. To investigate the origin of the above double melting behavior, the melting behavior after isothermal crystallization was analyzed with differential scanning calorimetry, wide-angle X-ray diffraction, and small angel X-ray scattering techniques. The double melting of the crystallized samples can be explained by the model of two populations of lamellae, the double peaks of low and high temperatures are contributed to the melting of the small lamellae produced by secondary crystallization and that of the major crystals formed in the primary crystallization process, respectively. Spherulitic growth rates of the neat PLA and PLA/MCB composite were analyzed and the occurrence of a regime transition was demonstrated. For the PLA, a clear regime transition was observed at around 125 °C. For the PLA/MCB, it occurred at 130 °C.

The rodent is one important component of an ecosystem; however, abundance of rodents may have negative effects to humans. Based on a seasonally breeding model and the logistic model, the effect of impulse lethal control and impulse contraception control on rodent population dynamics is investigated. The existence and stability of the periodic solution were analyzed. The condition of rodent population dying out is the same for lethal and contraception control. However, the process of rodent population tending to a stable periodic solution is different obviously. Under lethal control, the rodent population tends to a stable periodic solution more quickly, whereas under contraception control, the rodent population develops slowly.