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Down-the-hole (DTH) hammer drilling with reverse circulation is a novel, mobile, high-speed drilling system suitable for the specific requirements of mine rescue. This technology can be applied to shorten the rescue time during mine accidents. The performance of reverse circulation (RC) drilling depends on the structural design of the drill bit. An orthogonal experimental design is executed to investigate the effect of the structural design parameters of the large-diameter drill bit for drilling rescue wells on the cutting carrying capacity and reverse circulation performance. This study employs computational fluid dynamics (CFD) software to solve the Navier–Stokes equation for three-dimensional steady flow and calculate the flow field around the drill bit to evaluate the RC efficiency. Six key geometric parameters were proven to have a direct influence on the RC performance, including the diameter of suction nozzles Dn, the length of nozzles L, the quantity of nozzles N, the diameter of the pilot hole Dg, the inclination angle of nozzles θs, and the deflection angle of nozzles θd. The CFD simulation experiments were implemented according to the orthogonal array L18(37) and were analyzed using the range, variance, and regression analysis. A mathematical model was developed for the RC efficiency to understand the effect of the factors. The results show that the diameter of suction nozzles Dn has an essential effect on the RC performance of the drill bit. An ideal combination is Dn = 20 mm, L = 50 mm, N = 3, Dg = 50 mm, and θs = 35°, θd = 10°, which was obtained through variance analysis and validated via CFD simulation for higher efficiency. To verify its real performance, a large-diameter RC drill bit with a diameter of 1.2 m was manufactured and tested in the field. The result demonstrated that the drill bit had excellent cutting transport and reverse circulation performance. [ABSTRACT FROM AUTHOR]

Although pneumatic down-the-hole (DTH) hammers have good performance of high penetration rate and minimal deviation tendency in the vertical section of oil and gas wells, they have not been successfully used in directional drilling due to drill tool wear and wellbore disturbance. Herein, we developed a novel type of pneumatic DTH hammer with a self-propelled round bit to overcome the technical difficulties of directional drilling. Nonlinear dynamic modeling developed by the authors was used to analyze the working principle and performance of the novel DTH hammer. The kinematics and dynamics simulation of this hammer were carried out using MATLAB language, and the motion law of the piston was revealed. The performance of the novel hammer was numerically simulated and evaluated by considering fluctuations of the front and rear chamber pressure, impact energy, acceleration, and frequency. The results show that our novel DTH hammer's working principle is feasible and has an adequate structural design. The simulation results demonstrate reasonable design parameters. Compared to the numerical results for conventional DTH hammers, the velocity and acceleration of the piston of the novel hammer changed smoothly. The frequency was slightly higher than that of conventional hammers, while other parameters were nearly equal. The novel DTH hammer can be used in directional drilling, trenchless drilling, and seabed sampling drilling. [ABSTRACT FROM AUTHOR]

Adverse weather has been recognized as an important factor to affect travelers' activity plans in departure time, transport mode, route taken, or cancellation. In the storm, road waterlogging degrades the capacity of road networks and the service quality of transit systems, which further may affect the supply and demand for transit. Based on a typical case in Shanghai that commuters have no easy access to metro service, this paper aims to explore how transit passengers adapt to different situations in the storm and what emergency plans should be taken accordingly. Derived from the revealed preference (RP) and stated preference (SP) survey results for experienced transit commuters, a nested logit (NL) model was developed to describe the travel behavior of transit commuters. Six alternatives, Direct Bus, Bus + Bus, Metro, Bus + Metro, Taxi, and Cancel Trip, and three storm scenarios were set for transit commuters in this case. Estimated parameters indicate that, in storm weather, crowdedness is less considered by transit commuters, and transfer times, walking time, in-vehicle time, and waiting time have negative effects on the selection of the corresponding alternative, whereas the impact of taxi fare is positive since the higher fare is usually accompanied by worse weather and traffic condition. Sensitivity analysis shows that walking time to metro station, in-vehicle time, and waiting time at a bus stop are the most critical factors leading to transit ridership reduction in the storm. According to this, three possible plans for the transit operator, shuttle bus to the metro station (P1), information announcement (P2), and route adjustment (P3), are simulated and compared. We recommend adopting P2, P2 + P3, and P1 + P2 + P3 in turn with the increase of road waterlogging. These findings have important practical implications for developing transit emergency management plans and serve as references for the transit agencies and operators. [ABSTRACT FROM AUTHOR]

Infectious hypodermal and haematopoietic necrosis virus (IHHNV) is a major viral pathogen in cultured penaeid shrimp. IHHNV has many hosts, mainly including crustaceans. It has recently been reported that Procambarus clarkii can be infected by IHHNV. In the present study, we studied the hepatopancreas of P. clarkii by transcriptome high-throughput sequencing to analyze the response of P. clarkii to IHHNV infection. After de novo assembly, there were 400,340,760 clean reads. A total of 237 differentially expressed genes (DEGs) were obtained, including 77 significantly up-regulated unigenes and 160 significantly down-regulated ones. The expression levels of 12 immune-related DEGs were validated by qRT-PCR, substantiating the reliability of RNA-Seq results. The enrichment analysis of DEGs showed that the immune-related pathways were closely related to apoptosis and phagocytosis. Moreover, a large number of pathways related to metabolic function were down-regulated, suggesting that IHHNV infection might affect the growth of P. clarkii. • The response of Procambarus clarkii to IHHNV infection was studied by transcriptome high-throughput sequencing. • A total of 237 differentially expressed genes (DEGs) were obtained. • The DEGs immune-related enrichment pathways were closely related to apoptosis and phagocytosis. • Down-regulated metabolic-related pathways suggested that IHHNV infection might affect the growth of P. clarkii. [ABSTRACT FROM AUTHOR]

[Display omitted] • CFD method and a novel experimental device were used to study the physics of multiphase flow associated with the cleaning process. • Air influx was measured under the different conditions of ROP, cuttings diameter, and water yield. • The influence of ROP, cuttings diameter, and water yield on air influx was revealed. • Cuttings velocity and pressure drop could be influenced by ROP, cuttings diameter, and water yield. In reverse circulation (RC) down-the-hole hammer (DTH) drilling, hole cleaning has a great impact on reducing accidents and improving efficiency. There is a technical difficulty in RC drilling to select the minimum air influx while keeping cuttings discharged smoothly according to different water invasion conditions. A novel experimental device was used to study the physics of multiphase flow associated with the cleaning process. Air influx required for cuttings transport was measured under different conditions in Rate of Penetration (ROP), cuttings diameter, and water yield, and influence among three factors were revealed. Furthermore, the computational fluid dynamic (CFD) method simulated and analyzed multiphase flow behavior. The results show that factors of ROP, cuttings diameter, and water yield obviously impact minimum air influx during the cuttings transport process. The accuracy and credibility of CFD method have been confirmed on account of reasonable agreement with experimental data (a relative error of less than 14% is achieved). The CFD simulation of multiphase transport reveals that cuttings velocity and pressure drop could be influenced by ROP, cuttings diameter, and water yield. Therefore, these factors should be carefully characterized during air RC drilling and hole cleaning to maximize the efficiency of cuttings transport. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel SYBR Green-based RT PCR method specifically amplifies IHHNV. • This method showed no cross reaction with the other five pathogens. • The assay can detect one single copy of IHHNV plasmid DNA. • 80% of IHHNV-fed Procambarus clarkii samples were IHHNV positive. • IHHNV can heavily infect the gill of P. clarkii. Abstract Infectious hypodermal and haematopoietic necrosis virus (IHHNV) infects many crustacean hosts, including cultured penaeid shrimp. In the present study, we aimed to develop a novel sensitive SYBR Green-based real-time PCR method to specifically amplify DNA fragments of IHHNV. Our newly developed real-time PCR method with a 195-bp amplicon specifically detected IHHNV and showed no cross reaction with white spot syndrome virus (WSSV), hepatopancreatic parvovirus (HPV), Enterocytozoon hepatopenaei (EHP), infectious myonecrosis virus (IMNV) and yellow-head virus (YHV). This method could detect as low as one single copy of IHHNV plasmid DNA, more sensitive than other SYBR Green-based real-time PCR methods and less expensive and more convenient than the TaqMan probe-based real-time PCR. Moreover, our data using the newly designed method showed that 80% of IHHNV-fed Procambarus clarkii samples were IHHNV positive. Our findings further confirmed that P. clarkii can be infected by IHHNV. [ABSTRACT FROM AUTHOR]

This study introduces a new process for the fabrication of an electrode/ceramic multilayer device that uses a mixture of base and noble metals (Cu and Ag) as the inner electrode and is co-fired in air. In order to protect the Cu base metal when exposed to air, the Cu powder was sequentially coated with Ag nanoparticles using a wet process, and borosilicate glass using a sol-gel process. The degrees of oxidation and shrinkage of the glass-coated CuAg during the co-firing process were investigated. The glass-coated CuAg survived without the formation of copper oxide during the binder-burnout process in air at 500 °C. The CuAg was stable and unoxidized even when further heated to 950 °C, which is ascribable to the protection provided by the Ag layer to the Cu exposed to the oxidative atmosphere. The glass-coated CuAg exhibited complicated shrinkage behavior that was similar to that of glass at low temperatures, and to Ag and Cu densification at high temperatures. To examine the electrical performance of the glass-coated CuAg as an inner electrode, a CuAg/(Bi 0.37 Na 0.37 Sr 0.26 )TiO 3 (CuAg/BNST) multilayer-ceramic material was prepared using a conventional tape-casting and stacking procedure. The CuAg-paste binders were evaporated at 500 °C in air, and the CuAg electrode was then sintered at 950 °C in air. The electromechanical performance of the CuAg/BNST ceramic device is similar to that of a AgPd/BNST device, indicating that it can potentially be used as the inner electrode in a multilayer device. [ABSTRACT FROM AUTHOR]

Infectious hypodermal and haematopoietic necrosis virus (IHHNV) is a major viral pathogen in cultured penaeid shrimp. IHHNV has many kinds of hosts, especially those in crustacean. Freshwater crayfish Procambarus clarkii is one of widespread crustaceans, which can be infected by several penaeid shrimp viruses. However, it is still unknown whether P. clarkii is susceptible to IHHNV infection. In this study, IHHNV positive samples were found in wild P. clarkii samples. In IHHNV injection experiment, 100% of P. clarkii samples showed IHHNV positive and enlarged nuclei could be observed in P. clarkii gill sections. These results suggested that P. clarkii could be infected by IHHNV both naturally and experimentally. Statement of relevance The freshwater crayfish P. clarkii could be infected by IHHNV naturally and experimentally. P. clarkii imposes the potential risk of transmitting IHHNV to penaeid shrimp. [ABSTRACT FROM AUTHOR]

[Display omitted] • A metal fatty acid was used as process control agent (PCA) in the ball milling for nanostructured bulk thermoelectric materials. • Particle growth during sintering was suppressed and nanoinclusions were formed in matrix through the simple and scalable process. • The sintered pellet of Bi–Sb–Te powder ball-milled with iron stearate showed enhanced thermoelectric performance at high temperature. Nanostructuring of bulk thermoelectric materials has attracted interest as a promising approach to improve the thermoelectric performance by lowering the thermal conductivity through phonon scattering. In the present study, a metal fatty acid, which is widely used as a precursor that decomposes to form nanoparticles in colloidal chemistry, was used as a process control agent (PCA) in the ball milling for nanostructured bulk thermoelectric materials. A p-type Bi–Sb–Te alloy was ball-milled with different amounts of iron stearate PCA and sintered into bulk pellets. Microstructural analysis clearly showed that particle growth during sintering was suppressed and nanoinclusions were introduced in matrix, which resulted in an increased interface density and low thermal conductivity. As a result of further analysis of the decrease in thermal conductivity, it was found that the bipolar thermal conductivity was reduced, and thus the ZT was improved at high temperature. [ABSTRACT FROM AUTHOR]

The spin Hamiltonian parameters and local structures are theoretically studied for Cu2+-doped alkaline earth lead zinc phosphate (RPPZ, R=Mg, Ca, Sr, and Ba) glasses based on the high-order perturbation calculations for a tetragonally elongated octahedral 3d9 cluster. The relative elongation ratios are found to be ρ≈3.2%, 4.4%, 4.6%, and 3.3% for R=Mg, Ca, Sr, and Ba, respectively, because of the Jahn-Teller effect. The whole decreasing crystal-field strength Dq and orbital reduction factor k from Mg to Sr are ascribed to the weakening electrostatic coulombic interactions and the increasing probability of productivity of nonbridge oxygen (and hence increasing Cu2+-O2− electron cloud admixtures) under PbO addition, respectively, with increasing alkali earth ionic radius. The anomalies (the largest Dq and the next highest k among the systems) for R=Ba are attributed to the cross linkage of this large cation in the network. The overall increasing order (Mg≤Ba

The electric cycling characteristics of Cu/0.2(PbMg 1/3 Nb 2/3 O 3)-0.8(PbZr 0.475 Ti 0.525 O 3) (PMNZT) multilayer ceramic actuators were investigated. Cu/PMNZT co-fired multilayer actuators were fabricated by conventional tape casting, lamination, and sintering at 950 °C in air with subsequent annealing at 225 °C or 400 °C under a hydrogen atmosphere. In such processes, annealing of the multilayer samples under a reducing atmosphere is an important factor in controlling the piezoelectric performance. Unipolar and bipolar electric fields were applied to the actuators to investigate the fatigue behavior of the multilayer ceramic actuators. The sample annealed at 400 °C showed significant degradation in the effective electromechanical coupling coefficient (k eff) and dynamic piezoelectric constant (d 33 *) after 1 × 108 electrical cycles, while the sample annealed at 225 °C showed less degradation. X-ray diffraction and X-ray photoelectron spectroscopy analyses were performed to evaluate the difference in crystalline structures as a function of annealing temperature. The k eff , d 33 *, polarization, and strain were measured and evaluated as a function of the number of cycles. The cyclic dependence of strain was fitted to a linear logarithmic stretched exponential law. The significant degradation of the sample annealed at 400 °C is attributed to the reorientation of oxygen vacancies formed upon annealing, which gives a rise to internal field in the ceramic layer. The degraded performance of cycled sample was refreshed by a heating at 500 °C in air. • The effect of the annealing temperature on the electric-cyclic fatigue of Cu-PMNZT was evaluated. • The annealing provided important insights into the degradation mechanisms during cycling. • The regeneration process is proposed based on these mechanisms. [ABSTRACT FROM AUTHOR]

We investigated whether prunetin affects the proteolytic activity, secretion, and gene expression of matrix metalloproteinase-3 (MMP-3) in primary cultured rabbit articular chondrocytes, as well as in vivo production of MMP-3 in the rat knee joint to evaluate the potential chondroprotective effect of prunetin. Rabbit articular chondrocytes were cultured in a monolayer, and reverse transcriptionpolymerase chain reaction (RT-PCR) was used to measure interleukin-1β (IL-1β)- induced expression of MMP-3, MMP-1, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4), and ADAMTS-5. In rabbit articular chondrocytes, the effects of prunetin on IL-1β-induced secretion and proteolytic activity of MMP-3 were investigated using western blot analysis and casein zymography, respectively. The effect of prunetin on MMP-3 protein production was also examined in vivo. The results were as follows: (1) prunetin inhibited the gene expression of MMP-3, MMP-1, MMP-13, ADAMTS-4, and ADAMTS-5; (2) prunetin inhibited the secretion and proteolytic activity of MMP-3; (3) prunetin suppressed the production of MMP-3 protein in vivo. These results suggest that prunetin can regulate the gene expression, secretion, and proteolytic activity of MMP-3, by directly acting on articular chondrocytes. [ABSTRACT FROM AUTHOR]

The members of the phosphatidylinositol 3-kinase-related kinase (PIKK) family play vital roles in multiple biological processes, including DNA damage response, metabolism, cell growth, mRNA decay, and transcription. TRRAP, as the only member lacking the enzymatic activity in this family, is an adaptor protein for several histone acetyltransferase (HAT) complexes and a scaffold protein for multiple transcription factors. TRRAP has been demonstrated to regulate various cellular functions in cell cycle progression, cell stemness maintenance and differentiation, as well as neural homeostasis. TRRAP is known to be an important orchestrator of many molecular machineries in gene transcription by modulating the activity of some key transcription factors, including E2F1, c-Myc, p53, and recently, Sp1. This review summarizes the biological and biochemical studies on the action mode of TRRAP together with the transcription factors, focusing on how TRRAP-HAT mediates the transactivation of Sp1-governing biological processes, including neurodegeneration. [ABSTRACT FROM AUTHOR]

Abstract: The haemocyte count, phenoloxidase (PO) activity, specific α2-macroglobulin (α2-M) activity, respiratory burst, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, phagocytic activity, and clearance efficiency against Vibrio alginolyticus were examined when the white shrimp Litopenaeus vannamei (10.42±2.0g) were immersed in seawater (34‰) containing different concentrations of saponin (0, 0.5, 1 and 2mgL−1) for 24, 48 and 72h. Hyaline cells (HC), the total haemocyte count (THC), specific α2-M activity, respiratory burst, SOD activity, and GPx activity directly increased with the saponin concentration, whereas PO activity was inversely related to the saponin concentration. White shrimp L. vannamei that were immersed in saponin at 1 and 2mgL−1 showed increased phagocytic activity and clearance efficiency to V. alginolyticus over 48–72h. In another experiment, shrimp immersed in seawater containing different concentrations of saponin after 72h were challenged with V. alginolyticus at 3.2×105 colony-forming units (cfu)shrimp−1, and then placed in seawater. The survival rate of shrimp immersed in seawater containing saponin at either dose was significantly higher than that of control shrimp after 12h, as well as at the termination of the experiment (5days after the challenge). It was therefore concluded that L. vannamei immersed in water containing saponin at 2mgL−1 or less exhibited an immunomodulatory effect, as well as protection against V. alginolyticus infection. [Copyright &y& Elsevier]

This paper describes an investigation of the interface of a multilayer device consisting of a Pb-free ferroelectric material (Bi 0.37 Na 0.37 Sr 0.26)TiO 3 (BNST) and a base metal (Cu)-noble metal (Ag) mixture that were co-fired in air and a reducing atmosphere. The stability of the interface between CuAg inner electrode layer and the BNST ceramic layer was evaluated with regard to the Gibbs free energy using the Ellingham diagram and interdiffusion of the metallic electrode elements. The CuO and Ag were utilized as raw materials for the internal electrode of multilayer ceramic devices. These devices were burned out and sintered in air, and an additional heat treatment was performed at 300 °C in N 2 (95 vol%)/H 2 (5 vol%) mixed gas to convert CuO into Cu. In the process of co-firing, the diffusion of Cu from the CuAg electrode layer caused the BNST ceramic layer to transform from a ferroelectric phase into a relaxor phase. This was confirmed via scanning electron microscopy and transmission electron microscopy, and by measuring the temperature dependence of the strain and polarization behaviors of CuAg/BNST devices with different ceramic-layer thicknesses (18–126 μm). The thin-layer (18 μm) sample exhibited electromechanical properties representing a strong relaxor phase, whereas properties corresponding to a mixed ferroelectric/relaxor phase were observed in the thick-layer (126 μm) sample. Additionally, the point of transition from the ferroelectric to relaxor phase (T r-f) of the sample device with a ceramic-layer thickness of 126 μm was higher than that of the sample with a ceramic-layer thickness of 18 μm. This difference was due to the reduction in the stability of the ferroelectric phase, which was caused by the diffusion of Cu into the ceramic layer of the multilayer device. • We report the microstructure and properties of a co-fired CuAg/(Bi 0.37 Na 0.37 Sr 0.26)TiO 3 multilayer piezoelectric device. • CuAg/(Bi 0.37 Na 0.37 Sr 0.26)TiO 3 was sintered at 950 °C in air and additionally heated at 300 °C in N 2 /H 2 (reducing atmosphere). • Cu diffusion from the CuAg electrode layer to the BNST ceramic layer induces the change in ceramic phase. • Significant change in polarization and strain was observed with various ceramic layer thicknesses. [ABSTRACT FROM AUTHOR]

Brain homeostasis is regulated by the viability and functionality of neurons. HAT (histone acetyltransferase) and HDAC (histone deacetylase) inhibitors have been applied to treat neurological deficits in humans; yet, the epigenetic regulation in neurodegeneration remains elusive. Mutations of HAT cofactor TRRAP (transformation/transcription domain-associated protein) cause human neuropathies, including psychosis, intellectual disability, autism, and epilepsy, with unknown mechanism. Here we show that Trrap deletion in Purkinje neurons results in neurodegeneration of old mice. Integrated transcriptomics, epigenomics, and proteomics reveal that TRRAP via SP1 conducts a conserved transcriptomic program. TRRAP is required for SP1 binding at the promoter proximity of target genes, especially microtubule dynamics. The ectopic expression of Stathmin3/4 ameliorates defects of TRRAP-deficient neurons, indicating that the microtubule dynamics is particularly vulnerable to the action of SP1 activity. This study unravels a network linking three well-known, but up-to-date unconnected, signaling pathways, namely TRRAP, HAT, and SP1 with microtubule dynamics, in neuroprotection. [ABSTRACT FROM AUTHOR]

The effects of copper metal organic decomposition (Cu MOD) ink on the electrical and mechanical properties of SWCNT-based flexible transparent electrodes were investigated. In particular, we designed and demonstrated Cu MOD ink as bonding agents between oxidized SWCNT (Ox-SWCNT) and the polyethylene terephthalate (PET) substrate. PET substrates were surface-treated via plasma etching, and ultraviolet/ozone (UV/O 3) treatment was conducted for enhancing the dispersion of SWCNTs. Subsequently, spray coating of numerous times with Ox-SWCNT dispersion and once with Cu MOD ink was applied to the PET substrates at low temperatures. In this way, a robust, flexible, and transparent Ox-SWCNT/Cu@PET composite electrode was fabricated. The as-prepared Ox-SWCNT/Cu@PET composite electrode exhibited good properties, with a sheet resistance of 483.9 Ω/sq and transmittance of 82.1%. Even after 10000 bending cycles and 100 peel-off times, the resistance was only increased by factors of 1.07 and 1.12, respectively, confirming good mechanical robustness. In addition, the electrode exhibited excellent environmental stability; its electrical resistance was only increased by a factor of 1.35 after subjected to harsh environmental conditions (85 °C, 85% relative humidity) for 48 h. These results indicate that the Ox-SWCNT/Cu@PET composite electrodes are promising for wide application as FTCEs. [Display omitted] • Oxidation of SWCNTs and etching of PET enhanced dispersibility and wettability. • Cu NPs from Cu MOD ink improved electrical and mechanical properties of electrodes. • Cu NPs between Ox-SWCNTs and substrate served as bonding agents. • The composite electrodes exhibit good optical, electrical, and mechanical properties. • They can be used in FTCEs with excellent mechanical and environmental stability. [ABSTRACT FROM AUTHOR]

Cu–(0.7Pb(Mg 0.67 Nb 0.33)TiO 3 –0.3Pb(Zr 0.48 Ti 0.52)O 3)(PMNZT) multilayer actuators were prepared using a sequence of ceramic layer tape-casting, on-ceramic electrode printing, lamination, co-firing in air, and soaking in aqueous N 2 H 4 at 25–100 °C. The employed wet reduction protocol converted the Cu 2 O produced in the electrode layers upon co-firing to Cu, while keeping the composition and structure of the PMNZT ceramic layers unaffected. Nano-pores were converted into macro-pores with increasing reduction temperature and time. This reduction process was controlled by the kinetics, which is attributed to the open structure of the electrode resulting from the presence of a sacrificial polymer (polyvinylidene difluoride, PVDF) particles. This resulted in a short path of hydrogen diffusion in the inner electrode layers. The pore size and population affected the electrical conductivity of the electrode and the performance of the PMNZT ceramics. To address this issue, the sample was immersed in aqueous HSO 4 at 60 °C to fill the pores in the electrode layers, thereby mitigating their effect on electrical conductivity. The samples prepared using wet reduction and filling processes exhibited the same piezoelectric properties as the bulk PMNZT sample. • A novel fabrication process of piezoelectric multilayer actuator consisting of base metal inner electrode and lead-based ceramic was proposed. • Wet reduction for piezoelectric actuator fabrication is designed and proven in this study. [ABSTRACT FROM AUTHOR]

TiB 2 particle reinforced Al7050 matrix homogeneous composites (HC), TiB 2 /Al7050 three-layer conventional linear gradient functionally gradient materials (TFGM), and TiB 2 /Al7050 five-layer functionally gradient materials with a bionic structure (FFGM) were successfully prepared using vacuum hot-pressed sintering (VHS) method. The effects of gradient structure and TiB 2 particle content on the microstructural characterization and mechanical properties of these composites were investigated. The results demonstrate that the bending strength of all composites improves with the increase in TiB 2 content. Comparatively, the bending strength of functionally gradient materials (FGM) are generally superior due to a combination of the interlayer strength of each layer, heterogeneous deformation-induced strengthening, strength-plasticity synergy of the whole material, and synergistic interlayer strengthening under strong bonding. Notably, the enhancements in bending strength and strain exhibited by FFGM are more pronounced, highlighting its "soft-hard interleaved" and "strong-tough complementary" structural pattern. The research provides valuable insights for the application and further development of FGM. [ABSTRACT FROM AUTHOR]

A computational fluid dynamics (CFD) study was conducted to investigate the effect of several important factors on the dust control performance of a down-the-hole (DTH) air hammer drill bit for reverse circulation drilling in mines. It was shown that an increasing number of suction nozzles or inclination angles of suction nozzles was advantageous to improve dust control performance of the drill bit. Lowering the location of suction nozzles in the drill bit body is another way to increase its ability to control dust. There exists a critical diameter of suction nozzles for dust control performance. A series of experimental tests in the laboratory were carried out to validate the results of CFD modelling. It was shown that the CFD simulation results were in good agreement with experimental data. A prototype of the drill bit was built for testing in laboratory experiments. The same prototype was field-tested by drilling vertically downward exploration boreholes in one of the largest Molybdenum Ore Districts in Luanchuan of Henan Province, China. Field test results indicate that the modified drill bit could control drilling dust effectively. No cuttings escaped from the borehole when it was used for downward drilling. The DTH air hammer drill bit has not been tested for drilling a vertically upward hole, and therefore, future studies are required to improve the suction capacity of the drill bit for drilling vertically upward holes. [ABSTRACT FROM PUBLISHER]

Abstract: The template reaction of o-phenylenediamine, 1-benzoylacetone and nickelous acetate tetrahydrate results in two structure isomers, 6,17-dimethyl-8,15-diphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecinatonickel (II) (2) and 6,15-dimethyl-8,17-diphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecinatonickel (II) (4). However, the latter has been neglected in the previous research because of its low yield in the template reaction. The mechanism of this template reaction is discussed. Though the steric hindrance between the phenyl ring and the benzo ring in 2 is greater than that in 4, the intermediate of the former shows better structural stability than that of the latter, leading to obviously higher final yield of 2 compared with that of 4. n-Butyl alcohol is used artfully to separate the crude product of the template reaction into almost pure 2 and a mixture of 2 and 4 in a mole ratio of 1:5. The free base of 2, 5,14-dihydro-6,17-dimethyl-8,15-diphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine (1), can be synthesized by demetalization of 2 with gaseous HCl. The same treatment to the mixture of 2 and 4 in a mole ratio of 1:5 leads to the free base of 4, 5,14-dihydro-6,15-dimethyl-8,17-diphenyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine (3). The neglected macrocyclic compounds 3 and 4 have been characterized unambiguously and their single-crystal structures have also been determined by X-ray diffraction analysis for the first time. [Copyright &y& Elsevier]

Efficient dye-sensitized solar cells (DSCs) were realized by using multiwalled carbon nanotubes (CNTs) as the counter-electrode catalyst. The catalytic layers were produced from an aqueous paste of mass-produced raw CNTs with carboxymethylcellulose polymer by low-temperature (70 °C) drying. We found that the highly disordered CNTs played the important role of increasing the fill factor of DSCs with electrolytes includinglarge molecules and that the presence of Li the counter charges for I3−/I−redox couples reduced the chemical stability when using the CNT catalyst. Our experiments showed that by replacing the conventional Pt catalyst and Li+based electrolyte with the proposed CNT catalyst and an electrolyte containing 1-butyl-3-methylimidazolium cations instead of Li, the energy conversion efficiency increased from 6.51% to 7.13%. This result suggests that highly defective CNT catalysts prepared by low-temperature drying are viable cost-effective alternatives for DSCs, as long as the electrolytes composition is optimized. [ABSTRACT FROM AUTHOR]

A reverse circulation Down-The-Hole (DTH) hammer drill bit in Casing-while-Drilling (CwD) processes is designed and applied to drilling under complicated formation. The drill bit is a special retractable drill bit with an exclusive reverse circulation gas channel. Using numerical simulations and experiments, the influence of the gas channel structure parameters of the drill bit, including the inner jet nozzles, flushing nozzles, suction channel, and other parameters, on its reverse circulation performance is analyzed, and the optimal gas channel structure parameters of the drill bit are determined to improve the reverse circulation effect. The results show that the flushing nozzles and inner jet nozzles have an important influence on entrainment performance. The entrainment rate η decreases as the flushing nozzle diameter increases and decreases as the inner jet nozzle diameter increases. An increase in the suction channel diameter can improve the reverse circulation effect of the drill bit. The spiral slot drill bit is more conducive to air being sucked into the central channel in the form of spiral flow, so it can improve the entrainment performance. The entrainment rate η can reach 23.4% with the optimum structured drill bit. [ABSTRACT FROM AUTHOR]

Plackett–Burman screening, factorial designs, and second-order response surface methodology (RSM) for medium optimization were employed for lovastatin production by a high-producing mutant of Aspergillus terreus. The method used was effective in screening for nutritional requirements in a limited number of experiments. In a 7-day fermentation, a 4.18-fold increase (i.e. 1.05 g/l) was obtained at (g/l): lactose (89.5), glycerol (30.2), peptone (6.0), soybean meal (SM) (4.2), glucose (20.0), and corn steep liquor (CSL) (10.0), respectively. In the procedure of medium optimization, the formation of compact and highly shaved-off pellets of A. terreus was critical for lovastatin production, where the optimal average core size was about 0.85–1.05 mm. The lovastatin-producing phase was further prolonged if feeding 0.1 g/l d- or d,l-methionine at 72 h. This resulted in a 20% increase at day 10. Feeding provided no benefit if this dosage was added initially, and the addition also did not stimulate lovastatin production while added at late idiophase. Special attention was given to an adverse effect if using l-methionine. [Copyright &y& Elsevier]

[Display omitted] • An inhibitor composed of alginates and silicates is introduced to prevent shale hydration. • The synergistic inhibition properties and mechanism of alginates and silicates were investigated. • The superior inhibition property was achieved by polymer adsorption and cation intercalation. • It provides a potential solution for wellbore stability by improving the rheological and filtration performance. High performance hydration inhibitors are recognized as an attractive solution to address wellbore instability associated with water-based drilling fluids. Nevertheless, conventional inhibitors still face a dilemma regarding the balance between inhibition performance and compatibility, including rheological and filtration properties. Herein, we proposed an organic–inorganic composite inhibitor that combines polymer adsorption and ion intercalation to provide synergistic inhibition properties. The results demonstrated that the composite inhibitors reduced the clay swelling rate from 50.7 to 22.4 % and increased shale recovery from 71.4 to 90.2 % compared with that in K 2 SiO 3 solution, revealing the synergistic inhibition properties between ion exchange and film coating effect. In addition, the hydrogen bonding interaction between potassium alginate (PA) and clay particles effectively alleviates performance deterioration of base fluids containing K 2 SiO 3 , as evidenced by the apparent viscosity increased from 14.0 to 35.5 mPa·s, plastic viscosity increased from 4.0 to 25.0 mPa·s and filtration loss reduced from 35.2 to 20.4 mL after rolling at 120 °C. The intermolecular interaction between clay and PA facilitates the adsorption of polysaccharide chains onto clay surface, which was confirmed by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). Moreover, X-ray diffraction (XRD), zeta potential and particle size distribution verified the suppression of electric double layers caused by K+ ions intercalation. This study validates the feasibility of organic–inorganic hybrid materials as shale hydration inhibitors, utilizing the synergistic effects of polymer adsorption and cation intercalation. Furthermore, the study highlights the great potential of combining PA with silicates to maintain wellbore stability. [ABSTRACT FROM AUTHOR]

Lignin has potential to serve as promising sunscreen agents as it has good ultraviolet (UV) absorption and antioxidant properties. However, the weak absorption capacity of lignin in the long-wave UV region (UVA, 320–400 nm) limits its further development. In this work, a spiropyran-modified lignin (DLSP) with photo-responsive property was prepared by in-situ construction of spiropyran (SP) structure in the demethylated lignin (DL). Due to the presence of SP moiety, the absorption of DLSP in the UVA region was significantly improved. Under UV irradiation, its absorption peak was redshifted as unconjugated SP form isomerized to conjugated merocyanine (MC) form, and the UVA/UVB ratio increased from 0.62 to 0.74. The free-radical scavenging ability of lignin could protect SP from photodegradation, which provided DLSP excellent fatigue resistance. DLSP were blended into creams to investigate its sunscreen performance. Results indicated that DLSP exhibited radiation-enhanced sunscreen performance, the sun protection factor (SPF) of cream containing 10 wt% of DLSP improved from 20 to 67 after 8 h of UV irradiation. Moreover, DLSP showed low skin penetration and good biocompatibility. These results provide a useful guideline for the rational design of sunscreens with special functionalities. • Photo-responsive lignin was prepared through an efficient one-pot strategy. • The introduction of spiropyran significantly improved the absorbance of lignin in UVA region. • The cream blend with photo-responsive lignin exhibited radiation-enhanced sunscreen performance. • Photo-responsive lignin showed low penetration and good biocompatibility. • This study provides a useful guideline for the rational design of sunscreens with special functionalities. [ABSTRACT FROM AUTHOR]

Lignin has potential to serve as promising sunscreen agents as it has good ultraviolet (UV) absorption and antioxidant properties. However, the weak absorption capacity of lignin in the long-wave UV region (UVA, 320–400 nm) limits its further development. In this work, a spiropyran-modified lignin (DLSP) with photo-responsive property was prepared by in-situ construction of spiropyran (SP) structure in the demethylated lignin (DL). Due to the presence of SP moiety, the absorption of DLSP in the UVA region was significantly improved. Under UV irradiation, its absorption peak was redshifted as unconjugated SP form isomerized to conjugated merocyanine (MC) form, and the UVA/UVB ratio increased from 0.62 to 0.74. The free-radical scavenging ability of lignin could protect SP from photodegradation, which provided DLSP excellent fatigue resistance. DLSP were blended into creams to investigate its sunscreen performance. Results indicated that DLSP exhibited radiation-enhanced sunscreen performance, the sun protection factor (SPF) of cream containing 10 wt% of DLSP improved from 20 to 67 after 8 h of UV irradiation. Moreover, DLSP showed low skin penetration and good biocompatibility. These results provide a useful guideline for the rational design of sunscreens with special functionalities. • Photo-responsive lignin was prepared through an efficient one-pot strategy. • The introduction of spiropyran significantly improved the absorbance of lignin in UVA region. • The cream blend with photo-responsive lignin exhibited radiation-enhanced sunscreen performance. • Photo-responsive lignin showed low penetration and good biocompatibility. • This study provides a useful guideline for the rational design of sunscreens with special functionalities. [ABSTRACT FROM AUTHOR]

In this study, the interannual variations of ichthyoplankton assemblages in the Taiwan Strait (TS) during the winters of 2007–2013 were determined. The cold China Coastal Current (CCC) and Mixed China Coastal Water (MCCW) intruded into the TS and impinged with the warm Kuroshio Branch Current (KBC) with annual variations. Consequently, the ichthyoplankton community in the TS was mainly structured into two assemblages characterized by differing environmental conditions. The composition of the warm KBC assemblage was relatively stable and was characterized by Diaphus B and Bregmaceros spp. By contrast, the cold MCCW assemblage demonstrated considerable variations over the years, with demersal Gobiidae and Scorpaenidae families considered the most representative. In addition, Benthosema pterotum and Trichiurus spp. were common in both KBC and MCCW assemblages. The distribution of the KBC assemblage demonstrated sharp boundaries in the frontal zones, whereas changes in the assemblage structure between the frontal zones were gradual for the MCCW assemblage, particularly when demersal taxa were dominant. Sea surface temperature and salinity were most strongly associated with variability in the assemblage structure during the study period. Thus, this paper provides a better understanding of long-term larval fish dynamics during winter in the TS. [ABSTRACT FROM AUTHOR]

In this study, porous sandwich structures based on barium zirconate titanate–barium calcium titanate (BZT–BCT) ceramics are investigated for energy harvesting applications. To improve the piezoelectric energy harvesting performance, porous sandwich structures based on the BZT–BCT ceramics produced by the tape casting method are designed to be optimum materials with high piezoelectric charge coefficient and low dielectric constant. The dense and porous layer are made of BZT–BCT ceramic sheets and a mixture of BZT–BCT ceramic and polyvinylidene fluoride (PVDF), respectively. Here, the PVDF is a sacrificial material that is volatilized in the burnout process, which results in the formation of pores within the microstructure. Depending on the volume fraction of the porous layer, the BZT–BCT ceramics are manufactured in proportions ranging from 0% to 100 vol%. The 20 vol% of the porous layer exhibits the highest figure of merit (FOM) of 4.53 p.m.2/N. When the volume fraction of the porous layer exceeds 20 vol%, the FOM sharply decreases. The stored energy is calculated by measuring the output voltage on the external capacitor (1 μF) through the full-bridge circuit connected to the specimen. The energy density is calculated by dividing the stored energy by the sample area. The sample with a 20 vol% of the porous layer has an energy density of 7.29 μJ/cm2, which is the highest value attained. Image 1 • Porous BZT–BCT ceramic layers are produced by means of the sacrificial template method. • The samples are manufactured depending on the volume fraction of the porous layer. • The highest FOM and energy density are found to be 4.53 p.m.2/N and 7.29 μJ/cm2, respectively. [ABSTRACT FROM AUTHOR]

Rock properties near the wellbore are particularly important for the development of geothermal wells, but few people have studied them. The mechanical properties of granite rock near the wellbore after percussive drilling and abrasive water jet (AWJ) perforation are analyzed and studied in this paper. The variation of P-wave velocity, stress-strain curve, tensile strength, uniaxial compressive strength, peak strain, elastic modulus, microscopic appearances of fractures with the distance from the wellbore is studied. The purpose is to provide theoretical and technical support for fracturing and perforation in geothermal resource development. The experimental results indicate that percussive drilling can generate a large number of impact fractures near the wellbore, which can reduce the mechanical properties of granite rock near the wellbore. Compared with the granite after conventional rotary drilling, the p-wave, tensile strength, compressive strength and elastic modulus of granite after percussive drilling can be reduced by 87.3%, 55.10%, 38.32%, 66.67%, respectively. In addition, we find that AWJ perforation can only produce a few fractures, that is to say, its effect on the mechanical properties of rock is not significant. The percussive drilling effect on the mechanical properties is much more intense than AWJ perforation. Percussive drilling can affect the wellbore in a range of 1.2–1.5 times the diameter of the wellbore, while AWJ perforation can affect the wellbore in a range of 0.4–0.6 times the diameter of the wellbore. On the other hand, although AWJ perforation cannot change the mechanical properties of granite rock near the wellbore significantly, the secondary fractures produced by AWJ perforation can connect the impact fractures produced by percussive drilling, forming crushed zones. It demonstrates that the assistant technique of percussive drilling can be a potential solution for the stimulation enhancement of geothermal resources. • The effect of percussive drilling and AWJ perforation on mechanical properties near the wellbore was investigated. • A novel vision for the granite rock damage distribution around the wellbore under percussive drilling and AWJ perforation. • The damage distance of percussive drilling and AWJ perforation to the granite rock near the wellbore was determined. [ABSTRACT FROM AUTHOR]

• A novel technique of hydraulic fracturing assisted by the DTH-hammer-induced impact fractures is proposed. • Complex fracture networks can be formed near the wellbore. • The novel technique can significantly reduce the fracturing pressure and improve the permeability near the wellbore. Hydraulic fracturing is one of the key technologies in geothermal development of hot-dry-rock (HDR) geothermal energy. How to reduce the fracturing pressure and enhance the fractures connectivity of HDR has become a hot issue. In this paper, we propose to use a down-the-hole (DTH) hammer to impact granite, which assist to create new artificial fractures similar to natural fractures or widen the existing fractures near the wellbore, consequently enhancing the connectivity of fractures during hydraulic fracturing. A series of experiments were conducted to verify the feasibility of this stimulation technique, including the observation and quantification of impact fractures, and the determination of fracturing pressure. In addition, numerical simulation of impact stress wave was carried out to explain the distribution of fractures. The results showed that the granite rock mass damage caused by percussive rotary drilling was about 5–7 times larger than that caused by diamond rotary drilling. Meanwhile, the distribution of fractures was characterized by regionalization, which was mainly attributed to the attenuation of impact stress wave, and the numerical results were consistent with the experimental observations. Laboratory experiment results of hydraulic fracturing indicated that the fracturing pressure of granite samples near the wellbore after percussive drilling had been greatly reduced, which was nearly 50% lower than that of conventional drilling. It indicates that the proposed multi-fractured stimulation technique of hydraulic fracturing assisted by the impact fractures induced by a DTH hammer can be a potential solution to solve the problems of hydraulic fracturing. [ABSTRACT FROM AUTHOR]

[Display omitted] • We present an oil-in-water nanoemulsion as a plugging agent to maintain wellbore stability under elevated temperatures. • The nanoemulsion enables great plugging properties by depositing superhydrophobic precipitation in micro-nano pores. • The superhydrophobic film possesses remarkable water repellency, durability, and thermal stability. • The hydrophobic film consists of long hydrocarbon chain grafted crystalline and amorphous silica. Wellbore instability associated with shale hydration and micro-nano pores is one of the most crucial concerns in deep oil and gas drilling operations. In this study, we present a nanoemulsion containing silicates and organosilanes to plug microfractures and mitigate shale hydration by forming a superhydrophobic film in situ on the shale surface via emulsion polymerization and sol–gel process, thereby improving the wellbore stability. At the temperature above 150 °C, the nanoemulsion forms a dense, superhydrophobic film in the pores and on the surface of ceramic sheets, reducing filtration loss by 84.3%. The core showed an increase in strength of 2.86% over the original shale after soaking in the nanoemulsion at 180 °C for 48 h. The shale cuttings covered with film reduced water uptake by 91.56%, thus improving water resistance. The film facilitates to maintain or even improve the rock strength by preventing water absorption and hydration. It also exhibits excellent thermal stability and dynamic water repellency properties at high temperature. We determined that the film consisted of tightly stacked nanofilaments of 5–20 nm in diameter and well-distributed nanospheres of 25–50 nm in diameter, which were identified as crystalline and amorphous symbiotic silica modified by long alkyl chains, respectively. Therefore, in order to overcome the wellbore instability encountered in deep well drilling, we propose a strategy in which the downhole temperature triggers the nanoemulsion to polymerize and seal the pores while simultaneously forming a hydrophobic film on the shale surface. Moreover, it is expected to have practical applications in drilling engineering due to its convenient fabrication, eco-friendly and cost-effective characteristics. [ABSTRACT FROM AUTHOR]

Highlights • This paper describes the relationship between properties and size of core material in BNKT-BNST ceramic composite. • BNKT-BNST composites showed the coexistence of ferroelectric and relaxor phases. • The large size and small population of ferroelectric BNKT seed give a rise to a significant decay in frequency dependence of polarization and strain. Abstract This study involves the microstructure tailoring of two types of ferroelectric and relaxor composites and their frequency-dependent large-signal properties. The ferroelectric seed of Bi 0.5 (NaK) 0.5 TiO 3 (BNKT) and a relaxor matrix of 0.74 Bi 0.5 Na 0.5 TiO 3 -0.26SrTiO 3 (BNST) with a ratio of 0.1 were synthesized via a solid-state reaction. Two types of BNKT ferroelectric seeds, namely a large-sized template-type (t-BNKT) and small-sized powder-type (c-BNKT), were prepared. Additionally, X-ray diffraction and microstructure analyses revealed that the addition of BNKT to BNST induced the formation of two phases (ferroelectric and relaxor). BNKT/BNST exhibited a combination of relaxor and ferroelectric phases, while the relaxor corresponded to the major phase in pure BNST. The t-BNKT/BNST composite exhibited a large-sized ferroelectric phase in the relaxor matrix with a small population, and the c-BNKT/BNST contained a small-sized ferroelectric phase with a large population of the relaxor matrix in the microstructure. In high-field applications, BNST exhibited pinch-type polarization behavior due to the transition from polar nanocluster to ferroelectric microscale domains in the relaxor matrix. The addition of t-BNKT and c-BNKT accelerated the coexistence of the ferroelectric and relaxor phases, thereby inducing pinch-shaped polarization with high remnant polarization and parabolic strain behavior with high negative strain. The pure BNST and t-BNKT/BNST exhibited a transition from the relaxor to ferroelectric phases at a high-field application over 4 kV/mm. Furthermore, the advent of the ferroelectric phase in c-BNKT/BNST led to a transition from short-range polar ordering to long-range ferroelectric ordering when a lower field (<3 kV/mm) was applied. However, the sample exhibited difficulties in reverse transition upon removal of the applied field. The electromechanical properties of c-BNKT/BNST and t-BNKT/BNST indicated a significant change in the frequency dependence of the polarization and strain, which was related to the presence of the ferroelectric phase. The aforementioned property was evaluated based on the decay in the polarization behavior. [ABSTRACT FROM AUTHOR]

An orthogonal experimental design method is employed to investigate the effect of the structural parameters of the drill bit used in the Casing-while-Drilling (CwD) technology on its rock cuttings carrying capacity and reverse circulation performance. The results of the range analysis indicate that diameter of inner jet nozzle has the most significant impact on the cuttings carrying capacity of the drill bit, followed by the diameter of flushing nozzle. While for the reverse circulation ability, the diameters of the flushing nozzles have a dominant impact, followed by the diameters of the inner jet nozzles. In addition, the cuttings carrying capacity and the reverse circulation effect of the drill bit can be improved by shrinking the inner jet nozzle or appropriately enlarging the flushing nozzle. Accordingly, the optimal structural parameters of the drill bit are determined. Through further experiments, the cuttings carrying efficiency and the entrainment ratio of the optimal drill bit are 99.57% and 20.36%, respectively. Moreover, the rotation speed of drill bit has a trivial effect on its performance. At any tested rotation speed, the entrainment ratio is greater than 20%, and all the rock cuttings can be carried out of the borehole bottom using the proposed drill bit with the optimal structure. To test its real performance, a large-diameter retractable drill bit with a diameter of 600 mm was manufactured and tested in field. The results demonstrated that this retractable drill bit had excellent cuttings carrying and reverse circulation ability. The average penetration rate of the drill bit reached about 1.7 m/h in the formation of weathered sandstone with argillaceous composition, which was 1.7 times greater than conventional mud drilling in the same area. [Display omitted] • A retractable drill bit was developed for using in Casing while Drilling. • The drill bit structure was optimized by orthogonal design method. • Cuttings carrying capacity and reverse circulation effect were investigated. • A drill bit with diameter of 600 mm was designed and tested in drilling field. [ABSTRACT FROM AUTHOR]

PPE68 is a Mycobacterium tuberculosis-specific protein which is absent from the vaccine strains of BCG. A panel of 14 PPE68-derived peptides predicted to bind to HLA-A*0201 was synthesized. The HLA-A*0201 restriction of these peptides was determined in T2 cell line and HLA-A*0201 transgenic mice. The specificity of peptides was assessed in pulmonary tuberculosis (TB) patients using IFN-γ enzyme-linked immunospot (ELISPOT) assay, and immunodominant peptides were further used to evaluate their diagnostic potential in HLA-A*0201-positive pulmonary TB patients. 13 out of 14 peptides were identified as high-affinity binders. Of these peptides, 12 peptides induced significant IFN-γ-secreting T cell response in transgenic mice and 9 peptides were efficiently recognized by peripheral blood mononuclear cells of 10 HLA-A*0201-positive TB patients. Four immunodominant HLA-A*0201-restricted epitopes (PPE68, PPE68, PPE68, and PPE68) were recognized by the most of 80 HLA-A*0201-positive TB patients (81, 86, 74, and 84 %, respectively). These epitopes may be used for a potential diagnosis of M. tuberculosis infection. [ABSTRACT FROM AUTHOR]

In this study, we set out to identify dengue virus serotype 2 (DENV-2)-specific HLA-A*2402-restricted epitopes and determine the characteristics of T cells generated to these epitopes. We screened the full-length amino-acid sequence of DENV-2 to find potential epitopes using the SYFPEITHI algorithm. Twelve putative HLA-A*2402-binding peptides conserved in hundreds of DENV-2 strains were synthesized, and the HLA restriction of peptides was tested in HLA-A*2402 transgenic mice. Nine peptides (NS4b 228–237 , NS2a 73–81 , E 298–306 , M 141–149 , NS4a 96–105 , NS4b 159–168 , NS5 475–484 , NS1 162–171 , and NS5 611–620 ) induced high levels of peptide-specific IFN-γ-secreting cells in HLA-A*2402 transgenic mice. Apart from IFN-γ, NS4b 228–237 -, NS2a 73–81 - and E 298–306 -specific CD8 + cells produced TNF-α and IL-6 simultaneously, whereas M 141–149 - and NS5 475–484 - CD8 + cells produced only IL-6. Moreover, splenic mononuclear cells (SMCs) efficiently recognized and killed peptide-pulsed splenocytes. Furthermore, each of nine peptides could be recognized by splenocytes from DENV-2-infected HLA-A*2402 transgenic mice. The SMCs from HLA-A*2402 transgenic mice immunized with nine immunogenic peptides efficiently killed DENV-2-infected splenic monocytes. The present identified epitopes have the potential to be new diagnostic tools for characterization of T-cell immunity in DENV infection and may serve as part of a universal epitope-based vaccine. [ABSTRACT FROM AUTHOR]

The impedance-graded material (IGM) systems can be used as a protective structure to attenuate the stress. Due to the fluidic oscillator of the down-the-hole (DTH) hammer made by cemented carbide was broken during the test, it is urgent to design a protective structure to decay the stress transferred to the fluidic oscillator. This paper studied the stress attenuation effect of Steel-Poly-ether-ether-ketone (PEEK) -layered-protective-structure (SPLPS) subjected to low-velocity impact loadings. The contact state of samples is measured by pressure-sensitive test paper. The experiments were carried out by the split Hopkinson pressure bar (SHPB) method. The stress attenuation effect of 5-layer SPLPS was tested at the different impact velocities. A three-dimensional numerical simulation model is established to simulate the SHPB experiments with the same boundary conditions. The stress attenuation effect of different layers of SPLPS is compared by numerical simulation. Besides, the influence of the thickness of steel-sheet and PEEK-sheet is investigated. And the SPLPS made for the DTH hammer has been tested in the hot dry rock drilling field. The results show that the data of numerical simulation are consistent with the SHPB experimental results. It is found that the different impact velocities do not change the contact state of the sample's end face. The stress attenuation ratio of 5-layer SPLPS in numerical simulation and experiment is 77%. The attenuation ratio increases rapidly when the number of SPLPS layers changes from 1 to 4. When the number of SPLPS layers exceed 4, the attenuation ratio does not increase significantly. Additionally, the thickness of 6 mm and 8 mm are suitable parameters for the SPLPS. The field test has proved that the SPLPS could protect the fluidic oscillator effectively. • A Steel-Poly-ether-ether-ketone (PEEK) layered protective structure (SPLPS) is designed for a fluidic DTH hammer. • The stress attenuation ratio of the 5-layer SPLPS is up to 77% under the low-velocity impact. • The SPLPS have the advantages of simple structure, high service life and low cost for engineering application. [ABSTRACT FROM AUTHOR]

The target strata of sandstone-type uranium deposits are usually located in the fragile and loose strata, which makes it difficult to obtain core samples; consequently, a novel ice coring device for loose sandstone-type uranium deposits is proposed to solve this problem. Experiments proved that the artificial sample can replace the natural sample, and the coring method has high reliability. Ensuring the allegro formation of an ice valve with a given cold source is critical for this coring system, and reducing the loss of cold energy with help of insulation layer is one of the methods to speed up the formation of ice valve. Since the diameter of the drill tool is limited by its working scenario, the thickness of insulation layer is limited to ensure the size of core. Therefore, this paper conducted laboratory experiments of the insulation layer with different thicknesses to study the effect of the insulation layer on the formation of the sand–ice valve. Results show that the insulation layer can reduce the loss of cold energy during the freezing process and significantly affect the formation time of the sand–ice valve. When the thickness of the aerogel insulation layer is 2 mm, the freezing time is 44% shorter than that without insulation layer. According to the tests, the novel ice coring device is expected to solve the coring problem in loose sandstone-type uranium deposits. [ABSTRACT FROM AUTHOR]

In this study, an acoustic emission (AE) sensor was fabricated using lead-free Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 (BZT–BCT) ceramics. The acoustic and electromechanical properties of the AE sensor were determined by the shapes of the piezoelectric ceramics. To optimize the AE sensor performance, the shapes of the ceramics were designed according to various diameter/thickness ratios (D/T) = 0.5, 1.0, 1.5, 2.0, 2.5, 3.0. The BZT–BCT ceramic with D/T = 1.0 exhibited excellent values of a piezoelectric charge coefficient (d33), piezoelectric voltage coefficient (g33), and electromechanical coupling factor (kp), which were 370 (pC/N), 11.3 (10−3 Vm/N), and 0.58, respectively. Optimum values of resonant frequency (fr) = 172.724 (kHz), anti-resonant frequency (fa) = 196.067 (kHz), and effective electromechanical coupling factor (keff) = 0.473 were obtained for the manufactured BZT–BCT ceramic with D/T = 1.0. The maximum sensitivity and frequency of the AE sensor made of the BZT–BCT ceramic with a D/T ratio of 1.0 were 65 dB and 30 kHz, respectively. [ABSTRACT FROM AUTHOR]

new non-planar saddle shaped macrocyclic ligand 4,11-dihydro-5,7,12,14-tetramethyldibenzo[ b,i][1,4,8,11]tetraazacyclotetradecine (Htmtaa) containing a six-coordinate germanium(IV) complex, Ge(tmtaa)(OOCH) ( 1), in which two axial formate ligands are in the trans positions, has been synthesized. IR, UV, mass, NMR spectroscopic study and elemental analysis have been performed to characterize the complex. The single crystal X-ray diffraction analysis shows that in the solid state, molecules of 1 are connected through intermolecular hydrogen-bond weak interactions to form a one-dimensional supramolecular network. The temperature dependence of the electrical conductivity data (240-300 K) for 1 indicates a region of falling dσ/d(1/T), suggesting 'semiconductor-like' charge transport in the stacking direction. The conductivity of 1 at room temperature is 6.1 × 10 S/cm. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the effects of short-term exposure to triamcinolone on cultured choroidal fibroblast (CFB) cells and retinal pigment epithelial (RPE) cells. Methods: To evaluate the effect of triamcinolone on cell proliferation, CFB and RPE cells were divided into three groups: a short-term exposure group; a longterm exposure group, and a non-treated control group. Cells in the short-term exposure group were briefly exposed (5, 15 or 30 mins) to triamcinolone (0.01 mg/ml, 1 mg/ml or mitomycin C (0.01 µg/ml, 1 µg/ml). Cells in the longterm exposure group were continuously incubated in culture medium containing the drug until assessment. The control group was cultured without drugs. Cell viability and the number of cells were assessed at day 5 after exposure. To investigate the direct toxicity of triamcinolone on confluent RPE cells, completely confluent cells were exposed to the drugs in the manner as described above. Cell viability was determined on days 0, 3 and 5 after treatment. Results: In the short-term exposure group, 1 mg/ml triamcinolone caused a significant reduction in the proliferation of CFB and RPE cells. The proliferation of CFBs decreased even with exposure to 0.01 mg/ml triamcinolone. In the longterm exposure group, triamcinolone and mitomycin C reduced the proliferation of both CFB and RPE cells. Even very short periods of exposure to triamcinolone caused a significant reduction in the viability of completely confluent RPE cells. Conclusions: Even short periods of exposure to triamcinolone inhibited the proliferation of fibroblasts and RPE cells and were significantly toxic to completely confluent RPE cells. [ABSTRACT FROM AUTHOR]

Utilization of the rotary–percussive drilling tools can help to reduce friction along the drill string and improve drilling performance in hard rock formations. However, intrinsic vibration and shock loads may severely damage the bottom hole assembly (BHA) and measurement while drilling (MWD). This paper investigates the dynamic response of fluidic hammer with hydraulic-damping-device, a rotary–percussive drilling tool which can provide forward percussion while eliminating harmful backward impact collisions. Descriptive statistical methods are introduced to accurately estimate the required damping length (RDL) and maximize the actual stroke length. In order to evaluate the influence of hydraulic-damping-device on vibration elimination, this paper discusses the effect of principal operating and design parameters on the dynamic responses of the fluidic hammer. In particular, a parametric model is fitted, in which the probability that backward impact collision is sufficiently eliminated is restricted to follow the probability density function. According to this function, when the damping stroke equals 10 mm, it is better than 99.999% to fully eliminate the possibility of backward collision. The improved understanding of the dynamic responses and some optimization proposals of a fluidic hammer will lead to the system reliability enhancement and cost optimization of the drilling engineering by eliminating the harmful shock and reducing shock-related tool failures. • The hydraulic-damping-device can completely eliminate the backward stroke impact collision. • A descriptive statistical approach was introduced to maximize the actual stroke length. • A parametric model was fitted to evaluate the probability that impact collision is sufficiently eliminated. [ABSTRACT FROM AUTHOR]

• An AWJ assisted back reaming technique based on percussion drilling is proposed. • This technique can improve the reaming performance and efficiency. • The optimal AWJ reaming parameters are obtained based on the premise of reducing non-production time. • Percussion drilling provides a new way for efficient development of the geothermal wells. Abrasive water jet (AWJ) technology is one of the fastest growing methods of cutting materials in recent years. Because percussion drilling can cause numerous impact cracks around the borehole, and these impact cracks can reduce the mechanical properties of the rock around the borehole. This makes it possible to improve AWJ reaming efficiency. The present paper investigates the influence of key jet parameters on AWJ reaming performance according to the specific problems encountered in the Gonghe geothermal well (GH-01). Additionally, the required time for AWJ reaming is analyzed and discussed. The results indicate that there is an existence of optimum value of jet standoff distance (s/d 0 = 3) for the AWJ reaming performance. Moreover, the high jet traverse speed will lead to deterioration of reaming performance. If the jet traverse speed is controlled under 50 mm/s, the slower the speed is, the better the reaming performance is. In the context of reaming a defined depth of rock, jet pressure has no significant effect on reaming performance. The requirement of reaming can be met by using jet pressure at 35 MPa. Although the effect of the inclined jet on penetration depth is better than that of the vertical jet, the vertical jet can produce a wider penetrate width. Compared with conventional reaming, the time spent on AWJ reaming is 55 %–67 % less than that of conventional reaming when the depth of reaming is 100 m. All the above merits have provided a theoretical foundation and experimental proof for the field application of the AWJ reaming technique. [ABSTRACT FROM AUTHOR]

To determine the effect of heating and water-cooling on the mechanical properties of the WC-Co coatings, we conducted a series of mechanical tests on the HVOF (high-velocity oxygen-fuel) sprayed WC-Co samples. These coatings were first heated to the target temperatures (200–800 °C), followed by rapid cooling with water. Mechanical properties were tested after thermal treatments. Microstructural changes were also observed using a scanning electron microscope and optical microscope. According to experimental results, the microhardness, residual stress and adhesive strength of the heated WC-Co coating changed significantly after water-cooling. As heating temperature rises, changes in these properties become more pronounced. However, the number of cycles has less effect on the mechanical properties of the coatings and the effect mainly occurs in the first 30 cycles. Compared with the argon-cooling method, water-cooling induces greater changes in the mechanical properties at higher target temperatures. This indicates that water-cooling can damage the heated WC-Co coatings more remarkably than the other cooling treatment. Nevertheless, after about 30 cycles, changes in mechanical become less pronounced. Additionally, cobalt content has little impact on the mechanical properties of the coating after heating and water-cooling. • The effects of heating and water-cooling on the WC-Co coatings were investigated. • Temperature is the main factor affecting the properties of the coating. • Phase transformation and crack growth affect the properties of the coating. • Reducing vibration of the hammer can increase the service life of the coating. [ABSTRACT FROM AUTHOR]

In the present study, the Alkoxide-Hydroxide sol-gel process is utilized for the synthesis of barium titanate-silver (BaTiO 3 –Ag) nanocomposite in an inert atmosphere. The high value of dielectric constant having less tangent loss is obtained along with increasing conductivity with Ag content. Moreover, by the inclusion of the conductive phase in BaTiO 3 , the increasing value of dielectric properties with decreasing Curie temperature is investigated. Sintering of composites was done at 1100 °C for 20 min by using microwave sintering, to improve the densification of ceramic nanocomposites in lesser time with uniform grain size. By increasing the silver content, dielectric constant and tangent loss increased until the percolation threshold (∼5% Ag) achieved and suppression of formation of conducting path in composite occurred due to adhesion of silver on barium titanate. Also, at T c in BaTiO 3 –Ag (3.5%), the highest value of dielectric constant (ε r) (∼9 × 104 with tangent loss ∼0.06; several times larger than pure BaTiO 3) was obtained due to well dispersion of silver particles in BaTiO 3 matrix. • Alkoxide-Hydroxide sol-gel method is used for the synthesis of barium titanate-silver (BaTiO 3 –Ag) Nanocomposite in inert atmosphere. • In current investigation, a detailed study on enhancement of dielectric permittivity and the influences of microwave sintering condition on the properties of Ag–BaTiO 3 composite is presented. • The effect of Ag nanoparticles on dielectric properties of BaTiO 3 matrix is investigated by using different concentration of silver in composite. [ABSTRACT FROM AUTHOR]