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1.
J Nanosci Nanotechnol ; 20(2): 1013-1019, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383099

RESUMO

Nanomaterial-based flexible strain sensors have developed rapidly in recent years. Here, we propose a flexible strain sensor based on polydimethylsiloxane with carbon nanotubes (CNTs) and graphene quantum dots (GQDs). Different weight ratios of CNTs and GQDs were used as the sensitive units of the strain sensors. After analyzing the results of current-voltage curves and the strain effects of the sensors, we concluded that the introduction of GQDs played an important role in improving the sensitivity of the sensors. The gauge factor of the as-prepared strain sensors ranges from 0 to 841.42.

2.
Opt Express ; 27(21): 31075-31086, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31684347

RESUMO

Recently, using various intelligent approaches to achieve the efficient inverse design of photonic nanostructures with predefined and appropriate functionalities has attracted considerable attention. We propose a method to design subwavelength metal-dielectric nanoantennas and optimize the scattering directionality using a Bayesian optimization approach. The nanoantennas consisted of three gold disks separated by two dielectric layers. The geometrical parameters were optimized in an intelligent and fully automatic process. We showed that with the aid of the machine learning method, strong forward scattering or backward scattering at a specific wavelength could be efficiently achieved. We further showed that unidirectional scattering in opposite directions at two separate wavelengths can be designed. Moreover, it is possible to exchange the forward and backward directionality at two target wavelengths. The multipole decomposition approach was applied to analyze the multipole moments of the scattering field up to the third order. In the optimized unidirectional nanoantennas the electric and magnetic dipole moments satisfied the Kerker or anti-Kerker conditions at the wavelengths of interest. Our results demonstrated the possibility of automatically designing nanoantennas for specific applications via a machine learning scheme.

3.
Chemosphere ; 242: 125195, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31683164

RESUMO

Fine particulate matter (PM2.5) pollution in Beijing was investigated based on field observation and air quality modeling. Measurement results showed that when using elemental carbon (EC) as the reference component, concurrent increases were observed in the relative abundances of sulfate, nitrate, organic carbon (OC) and water-soluble organic carbon (WSOC) when RH exceeded ∼65% during winter. The observed increases could not be explained by variations of primary biomass burning emissions, instead they likely pointed to heterogeneous chemistry and presumably indicated that formation of secondary inorganic and organic aerosols might be related during winter haze events in Beijing. Large gaps were found in winter when comparing the observational and modeling results. In summer, RH exhibited little influence on the observed sulfate/EC, OC/EC or WSOC/EC, and the observed and modeled results were in general comparable for the concentrations of sulfate, EC and OC. This study suggests that distinct yet poorly-understood atmospheric chemistry may be at play in China's winter haze events, and it could be a substantial challenge to properly incorporate the related mechanisms into air quality models.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31713705

RESUMO

This study investigated the effects of enzymatic hydrolysate of cottonseed protein (EHCP) supplementation on the growth performance and intestinal health of nursery pigs in Thailand. A total of 180 newly weaned piglets were randomly allocated to 3 groups with 6 replicates in each group and 10 piglets per replicate. Nursery pigs were fed three diets containing 0, 1%, and 1.5% EHCP for 28-63 days of age. The results indicated that 1% EHCP supplementation increased average daily feed intake (ADFI) and average daily gain (ADG) and decreased feed conversion rate (FCR) in the numerical, suggesting that appropriate EHCP supplementation could numerically improve growth performance of nursery pigs in Thailand. Moreover, 1% EHCP supplementation significantly decreased intestinal crypt depth and diarrhea incidence and increased intestinal villus height to crypt depth ratio and fecal consistency, suggesting that optimum EHCP supplementation could improve intestinal morphology and decreased diarrhea incidence of nursery pigs in Thailand. Furthermore, 1% EHCP supplementation significantly improved intestinal glutathione (GSH) level and superoxide dismutase (SOD) activity and indicated that optimal EHCP supplementation could improve intestinal antioxidant capacity of nursery pigs in Thailand. Optimum EHCP supplementation numerically increased growth, significantly decreased diarrhea incidence, significantly improved intestinal morphology and antioxidant capacity of nursery pig in Thailand.

5.
J Neurophysiol ; 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31721638

RESUMO

Persistent inward currents (PICs) are widely reported in rodent spinal neurons. A distinctive pattern observed recently is staircase-like PICs induced by voltage ramp in serotonergic neurons of mouse medulla. The mechanism underlying this pattern of PICs is unclear. Combining electrophysiological, pharmacological and computational approaches we investigated the staircase PICs in serotonergic neurons of medulla in ePet-EYFP transgenic mice (P1-P7). Staircase PICs induced by 10-second voltage bi-ramps were observed in 70% of serotonergic neurons (n=73). Staircase PICs activated at -48.8±5 mV and consisted of two components with the first PIC of 45.8±51 pA and second PIC of 197.3±126 pA (n=51). Staircase PICs were also composed of low-voltage activated (LVA) sodium PIC (Na-PIC, onset -46.2±5 mV, n=34), high-voltage activated (HVA) calcium PIC (Ca-PIC, onset -29.3±6 mV, n=23) and HVA tetrodotoxin- and dihydropyridine-resistant sodium PIC (TDR-PIC, onset -16.8±4 mV, n=28). Serotonergic neurons expressing Na-PIC, Ca-PIC and TDR-PIC were evenly distributed in medulla. Bath application of 1-2 µM TTX blocked the first PIC and decreased second PIC by 36% (n=23, P<0.05). Nimodipine (25 µM) reduced the second PIC by 38% (n=34, P<0.001) without altering the first PIC. TTX and nimodipine removed the first PIC and reduced second PIC by 59% (n=28, P<0.01). Modeling study mimicked the staircase PICs and verified experimental conclusions that sequential activation of Na-PIC, Ca-PIC and TDR-PIC in order of voltage thresholds induced the staircase PICs in serotonergic neurons. Further experimental results suggested that the multiple components of staircase PICs play functional roles in regulating excitability of serotonergic neurons in medulla.

6.
Br J Nutr ; : 1-20, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31694733

RESUMO

Prior data on long-term association between habitual legume consumption and hypertension risk remained sparse. We aimed to evaluate whether total legume and subtype intakes were prospectively related to lower hypertension incidence among 8,758 participants (aged ≥30 years) from the China Health and Nutrition Survey 2004-2011. Dietary intakes were assessed by interviews combining 3-day 24-h food recalls and household food inventory weighing method at each survey round (median dietary assessment times during follow-up was three). Incident hypertension was identified by self-reports or blood pressure measurements. Multivariable Cox regression model was applied to estimate hazard ratio (HR) for hypertension across increasing categories of cumulatively averaged legume intake. For 35,990 person-years (median 6.0 years per person), we documented 944 hypertension cases. After adjustment for covariates, higher consumption of total legumes was significantly associated with a lower hypertension risk, with HR comparing extreme categories being 0.56 (95% CI 0.43-0.71; P for trend <0.001). Then we found that intakes of dried legumes (HR 0.53; 95% CI 0.43-0.65; P for trend <0.001) and fresh legumes (HR 0.67; 95% CI 0.55-0.81; P for trend <0.001) were both related to reduced hypertension risks. However, further classification of dried legumes revealed that the inverse association with hypertension substantially held for higher soybean (HR 0.51; 95% CI 0.41-0.62; P for trend <0.001) but not non-soybean intakes. In stratified analyses, the association of interest remained similar within strata defined by gender, body mass index, physical activity, smoking and drinking status; however, significant heterogeneity of results was detected across age strata (P for interaction = 0.02). Total legume intake related to a more pronounced decrease in hypertension risk for the elderly (≥65 years [HR 0.47; 95% CI 0.30-0.73; P for trend <0.001]), in contrast to that for the non-elderly. Our findings suggest inverse associations of all kinds of legume but may not non-soybean intakes with risk of developing hypertension.

8.
Mol Plant Pathol ; 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31701600

RESUMO

Plants have evolved powerful immune systems to recognize pathogens and avoid invasions, but the genetic basis of plant susceptibility is less well-studied, especially to oomycetes, which cause disastrous diseases in many ornamental plants and food crops. In this research, we identified a negative regulator of plant immunity to the oomycete Phytophthora parasitica, AtRTP5 (Arabidopsis thaliana Resistant to Phytophthora 5), which encodes a WD40 repeat domain-containing protein. The AtRTP5 protein, which was tagged with green fluorescent protein (GFP), is localized in the nucleus and plasma membrane. Both the A. thaliana T-DNA insertion rtp5 mutants and the Nicotiana benthamiana RTP5 (NbRTP5) silencing plants showed enhanced resistance to P. parasitica, while overexpression of AtRTP5 rendered plants more susceptible. The transcriptomic analysis showed that mutation of AtRTP5 suppressed the biosynthesis of endogenous jasmonic acid (JA) and JA-dependent responses. In contrast, salicylic acid (SA) biosynthesis and SA-dependent responses were activated in the T-DNA insertion mutant rtp5-3. These results show that AtRTP5 acts as a conserved negative regulator of plant immunity to Phytophthora pathogens by interfering with JA and SA signalling pathways.

9.
Artigo em Inglês | MEDLINE | ID: mdl-31703349

RESUMO

Although green process technology is vital to sustainable development, few articles focus on how to implement it from the perspective of firms. This article tries to answer this question. Being set as an antecedent of green process innovation, the influence of environmental management is analyzed and the influential path is elaborated. Hypotheses are tested by means of multivariate regression analysis and bootstrap method. The results show that environmental management is conducive to firms' green process innovation, and the influence is through zero-order routine replication and higher-order routine replication. The mediating effect played by the interaction between the two is stronger than that of the individual. Implications are given to academia and practitioners.

10.
Small ; : e1905240, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31755227

RESUMO

Microbial fuel cells (MFCs) can convert organics in wastewater directly to electricity, and improving oxygen reduction reaction (ORR) performance is critical to their development and future applications. Electrocatalytic ORR performance is determined by the intrinsic activity and accessible amounts of active sites. A surface nitrogen-enriched carbon coaxial nanocable (NCCN) is applied as an ORR electrocatalyst and combined with activated carbon (AC) with 80 wt% addition as a carbon-carbon composite air cathode in MFCs. The fully exposed nitrogen active sites of NCCN contribute to the enhanced ORR activity, while the graphitized core affords a rapid pathway for electron transportation. AC serves as a spacer to construct a porous framework with interconnected ion diffusion channels. This cathode thus exhibits a maximum power density of 2090 mW m-2 , 120% higher than commercial Pt/C electrocatalysts, and also 6% higher than the pure NCCN, indicating a synergistic effect between NCCN and AC. A high-performance NCCN-AC air cathode with a great promise for future MFC applications is reported and an effective strategy to bridge the electrocatalytic performance from nanomaterials to practical devices is presented.

11.
Adv Mater ; : e1905873, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31709660

RESUMO

Building aqueous acidic batteries is in its infancy. There are several sporadic attempts that show desirable electrochemical performance, especially rate stability and high power density. The direct use of a metal anode is regarded as the best protocol for fabricating metal-based batteries. However, introducing an acid-tolerant and electrochemically reversible metal anode into an acidic aqueous battery system remains a considerable challenge. In this work, copper (Cu) metal is used as a reversible metal anode to match acidic regimes with a nearly 100% deposition-dissolution efficiency. The reaction kinetics and mechanism of the Cu anode can be regulated by protons with 400% kinetic acceleration compared with a mild electrolyte. In addition, the anode exhibits a dendrite-free morphology after cycling due to the surface roughening effect, which is different from the morphologies of widely used Zn- and Li-metal anodes. When coupled with the Prussian blue analog as cathodes, the battery delivers ultrafast kinetics of 1830 W kg-1 at 75 C, which is comparable to the power performance of supercapacitors. Long-term cyclic stability is evaluated, where the capacity retention is 85.6% after 5000 cycles. Finally, flexible fiber-shaped acidic Cu-based batteries are demonstrated for potential wearable applications.

12.
Artigo em Inglês | MEDLINE | ID: mdl-31725385

RESUMO

To provide an effective and safe therapy to persons with neurological impairments, accurate determination of their residual volitional ability is required. However, accurate measurement of the volitional ability, through non-invasive means (e.g., electromyography), is challenging due to signal interference from neighboring muscles or stimulation artifacts caused by functional electrical stimulation (FES). In this work, a new model-based intention detection method that combines signals from both surface electromyography (sEMG) and ultrasound (US) sonography to predict isometric volitional ankle dorsiflexion moment is proposed. The work is motivated by the fact that the US-derived signals, unlike sEMG, provide direct visualization of the muscle activity, and hence may enhance the prediction accuracy of the volitional ability, when combined with sEMG. The weighted summation of sEMG and US imaging signals, measured on the tibialis anterior muscle, is utilized as an input to a modified Hill-type neuromusculoskeletal model that predicts the ankle dorsiflexion moment. The effectiveness of the proposed model-based moment prediction method is validated by comparing the predicted and the measured ankle joint moments. The new modeling method has a better prediction accuracy compared to a prediction model that uses sole sEMG or sole US sonography. This finding provides a more accurate approach to detect movement intent in the lower limbs. The approach can be potentially beneficial for the development of US sonography-based robotic or FES-assisted rehabilitation devices.

13.
Sci Rep ; 9(1): 17064, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31745165

RESUMO

The reduced-tillage (Rt) has been proposed as a strategy to improve soil organic carbon and soil total nitrogen pools. However, little is known of the role of the reduced-tillage compared with the organic (Org) and conventional (Con) management in the Songnen Plain of China. We studied the 4 yr effect of three management strategies (Con, Org and Rt management) on labile soil organic carbon (C) and nitrogen (N) pools, including variation in mineralizable carbon and nitrogen, microbial biomass carbon and nitrogen, dissolved organic carbon and nitrogen in the rotation of alfalfa-corn established in 2009. Soil characteristics including soil organic carbon (SOC), soil total nitrogen (STN), dissolved organic carbon (DOC), dissolved organic nitrogen (DON), microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) were quantified in samples collected during the 9 yr rotation of 5yr-alfalfa (Medicago sativa L.) followed by 4 yr corn (Zea mays L.). The mineralizable C was increased in the four years, and although not statistically significant, 12% higher in the fourth year under reduced-tillage than conventional management (268 kg ha-1). Soil organic C was increased by 30% under reduced-tillage compared to conventional management (15.5 Mg ha-1). Three management strategies showed similar labile N pools in the Con and Org management, but differed in the Rt management. Org management showed significantly lesser mineralizable and inorganic N compared to other strategies, but soil microbial community and comparable crop yield across management strategy in year 4, indicating more efficient N use for organic than other management strategy. In our conditions, reduced-tillage for corn cropping after five years of alfalfa grassland can accumulate labile C and N and improve N utilization to for crop yields in the forage-based rotations. These findings suggest an optimal strategy for using Rt management to enhance soil properties and crop yield in plantation soils and provide a new perspective for understanding the potential role of Rt management in plantation soil.

14.
J Control Release ; 316: 317-330, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31733293

RESUMO

Although microRNAs (miRNAs) function as the important tumor gene regulators, they still confront with many challenges in systemic delivery. Here, the amphiphilic gemcitabine-oleic acid prodrugs (GOA) binding miRNAs with hydrogen bond are assembled into nanoparticles (GOA/miR NPs) through hydrophobic interaction via denaturation-annealing processes and nano-precipitation technique. The non-cationic GOA/miR NPs with an average size of ~150 nm and a zeta potential of ~ - 15 mV exhibit a stable encapsulation of miRNAs with non-sequence selectivity. Either miR-122 or miR-34a encapsulated in the GOA/miR NPs is efficiently delivered into HepG2 cells and significantly downregulate the expression levels of target gene after lysosome escape and pH-responsive disassembly. Moreover, in vivo experiments demonstrate that the GOA/miR-122 NPs exhibit higher tumor accumulation. Compared to GOA micelles, GOA/miR-122 NPs displayed stronger tumor inhibition (73% regression) after intravenous injection in nude mice xenografted with HCC, along with rapid clearance in normal liver tissues. Furthermore, there is no significant influence on biochemical indicators and immune factors during the systematic administration of GOA/miR-122 NPs. The non-cationic GOA/miR NPs engineered by hydrogen bond interaction and hydrophobic forces show the enhanced synergistic antitumor efficacy and good biosafety, which will provide a potential nanomedcine for HCC treatment.

15.
Artigo em Inglês | MEDLINE | ID: mdl-31765321

RESUMO

This article studies the model-based event-triggered control (ETC) for the tracking activity of the underactuated surface vessel (USV). Following this ideology, the continuous acquisition of states is no longer needed, and the communication traffic is reduced in the channel of sensor to controller. The control laws are fabricated in the frame of an adaptive model, which is renewed with the states of the original system whenever the triggering condition is violated. In the scheme, both internal and external uncertainties are approximated by the neural networks (NNs). To decrease the computing complexity, the minimum learning parameters (MLPs) are involved both in the adaptive model and the derived controller. The adaptive laws of only two MLPs are devised, and their updating only happens at triggering instants. Using the MLPs, an adaptive triggering condition is further derived. To avoid the ``Zeno'' phenomenon in small tracking errors, a dead-zone operator is designed for the triggering condition. Furthermore, we incorporate the dynamic surface control (DSC) into the controller design, such that the jumping of virtual control laws at triggering instants is smoothed and the problem of ``complexity explosion'' is circumvented. Through the techniques of the impulsive dynamic system and the direct Lyapunov function, the parameter setting for the DSC is derived to guarantee the semiglobal uniformly ultimate boundedness (SGUUB) of all the error signals in the closed-loop system. Finally, the effectiveness of the proposed scheme is validated through the simulation.

16.
Artigo em Inglês | MEDLINE | ID: mdl-31766404

RESUMO

According to the number of environmental management practices implemented by the firm and the degree of integration of environmental management with other functions of the firm, this study divides environmental management into two dimensions: environmental management breadth and environmental management depth. We argue that the impact of environmental management breadth on manufacturing performance is moderated by environmental management depth. A survey data including 225 Chinese manufacturing firms is used to test the hypotheses. Results show that there is an inverted U-shaped relationship between environmental management breadth and manufacturing performance; the impact of environmental management depth is positive; meanwhile, environmental management depth moderates the relationship between environmental management breadth and manufacturing performance.

17.
Colloids Surf B Biointerfaces ; : 110642, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31744761

RESUMO

A biocidal composite unit with improved synergism, using one cationic quaternary ammonia salt (QAS) site to attract electronegative bacteria to three highly biocidal N-halamine sites, was designed for the first time and attached onto surface of magnetic silica coated Fe3O4 nanoparticles (silica@Fe3O4NPs) for superior biocidability, large killing area, and easy recyclability. Briefly, a compound containing one imide and two amide NH bonds, 2-(2,5-dioxoimidazolidin-4-yl)-N-(4-hydroxyphenyl)acetamide (DHPA), was prepared by amidation of hydantoin acetic acid with p-aminophenol. A biocidal precursor of one QAS site and three N-halamine sites was then constructed by alcoholysis of 3-triethoxysilylpropyl succinic anhydride with 2-(dimethylamino)ethan-1-ol to introduce a tertiary amine and subsequent esterification with DHPA to introduce three NH bonds. The triethoxysilyl groups in the precursor were hydrolyzed to silanol groups to condense with their counterparts on silica@Fe3O4 NPs. The surface of resultant NPs carried units each contains one QAS site and three N-halamine sites after quaternization and chlorination. The biocidal surface showed superior biocidability against Escherichia coli and Staphylococcus aureus than reported systems due to the improved synergism between multiple antibacterial groups of different types and was stable towards quenching-chlorinating process and storage. The successful design opens insight in the syntheses of more powerful biocides.

18.
Adv Mater ; : e1904815, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31746047

RESUMO

Helicity indicates the in-plane magnetic-moment swirling direction of a skyrmionic configuration. The ability to reverse the helicity of a skyrmionic bubble via purely electrical means has been predicted in frustrated magnetic systems; however, it has been challenging to observe this experimentally. The current-driven helicity reversal of the skyrmionic bubble in a nanostructured frustrated Fe3 Sn2 magnet is experimentally demonstrated. The critical current density required to trigger the helicity reversal is 109 -1010 A m-2 , with a corresponding pulse-width varying from 1 µs to 100 ns. Computational simulations reveal that both the pinning effect and dipole-dipole interaction play a crucial role in the helicity reversal process.

19.
Artigo em Inglês | MEDLINE | ID: mdl-31746521

RESUMO

Lithium-sulfur (Li-S) batteries are highly regarded as the next-generation energy storage devices because of their ultrahigh theoretical energy density of 2600 Wh kg -1 . Sulfurized polyacrylonitrile (SPAN) is considered as a promising sulfur cathode to substitute conventional carbon/sulfur (C/S) composite to afford higher Columbic efficiency, improved cycling stability, and potential high-energy-density Li-SPAN batteries which attract growing attentions. However, unstable Li metal anode critically threatens the actual performances of Li-SPAN batteries with limited lifespan and safety hazards . Considering Li metal can react with almost all kinds of electrolyte to generate a protective solid electrolyt e interphase ( SEI ), electrolyte r egulation is widely accepted as a vital and feasible strategy to protect Li metal anode in rechargeable batteries . In this review, basic principles and current challenges of Li-SPAN batteries are firstly addressed. Recent advances on electrolyte regulation towards stable Li metal anode in Li-SPAN batteries are summarized to afford design strategies of solvents, lithium salts, additives, and gel electrolyte. Finally, prospects for future electrolyte design and Li anode protection in Li-SPAN batteries are also discussed.

20.
Opt Lett ; 44(22): 5582-5585, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31730113

RESUMO

We demonstrate a four-stage silicon distributed traveling-wave photodetector (TWPD) whose input terminal is open-circuit so as to enhance the radio-frequency (RF) output power. In order to mitigate the bandwidth drop caused by the RF reflection at the open input terminal, photodetector (PD) units are aperiodically loaded on the TW electrode. With the aid of an equivalent circuit model, we optimize spacings between PD units and then improve the 3 dB bandwidth from 7 to 10 GHz. A good agreement between measurement and modeling is obtained. Thanks to the cancellation of the input termination impedance, maximum RF output powers of the device are 10.2 and 6.5 dBm at 5 and 10 GHz, respectively. The corresponding power conversion efficiencies are 7.0% and 3.2%.

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