Search

Previous studies have shown that Fe2O3 nanoparticles (Fe2O3 NPs) may be a potential form of fertilizer utilization. In recent years, heavy metal such as cadmium (Cd) pollution has become increasingly severe. The effects of Fe2O3 NPs on plant Cd absorption were not well understood. The aim of this study was to explore the effect of Fe2O3 NPs on the absorption of Cd by rice seedlings. In the present study, Fe2O3 NPs were sprayed on the leaves of rice seedlings (Hybrid Rice Y Liangyou 900) under hydroponic conditions with 50µM CdCl2. There were two series of spraying treatments, namely Fe2O3 NPs and FeCl3 bulk materials, and 4 kinds of concentrations (i.e., 0, 20, 50, 100 mg/L). The results showed that the addition of exogenous Cd2+ to the nutrient solution inhibited the growth of rice seedlings, which was reflected in dwarf plants, underdeveloped roots, and chlorotic leaves. Foliar application of FeCl3 and Fe2O3 NPs materials aggravated the inhibition of Cd2+ on rice seedling growth, resulting in further reduction of plant height. But the negative effects were more obvious especially at 50 mg/L FeCl3; Cadmium stress caused damage to DNA, which was manifested in the increase of 8-hydroxydesoxiguanosine (8-OHdG) content. Foliar application of two kinds of iron materials partially reduced the DNA damage of cadmium to shoot, and the mitigating effect of Fe2O3 NPs was more obvious than FeCl3. [ABSTRACT FROM AUTHOR]

As a new type of material, nanomaterials are used in various fields, and its application in the field of agriculture is gradually deepening. This article reviews the roles and advantages of nanomaterials in agricultural production, including the use of nanomaterials as fertilizers, pesticides, plant growth regulators and animal feed additives, sterilization, packaging materials, environmental improvements and so on, and made recommendations for the study of the application of nanomaterials in agriculture. [ABSTRACT FROM AUTHOR]

A reconstruction method of axially moving lenslet array (AMLA) was proposed. First, the dot-pattern reconstructed image was generated from a set of AMLA-recorded EIs using pixel-to-pixel mapping. Then, the empty pixels of dot-pattern reconstructed image can be filled by the average of the intensity values of all pixels that are corresponding to the empty pixels in each EI and determined through back projection. Using this proposed method, not only can the empty pixels be eliminated, but also the image quality is higher than conventional interpolation. Moreover, the axially moving gap can also be arbitrary, which breaks the limitation of the strict interpolation-free condition of the conventional reconstruction method. The feasibility of this method was verified by simulations and optical experiments. [ABSTRACT FROM AUTHOR]

Engineering nanoparticles (ENP) are increasingly getting into people's lives. Nanoparticles(NPS) are likely to enter soil components due to the release of particulate matter containing NP products. This paper summarizes the characteristics of heavy metals in soil. And systematically describes the ways in which nanoparticles enter the soil, the methods of migration and transformation in the soil, and the important factors influencing their migration in the soil. In the environment, the characteristics of soil (such as pH, soil type, organic matter content and test environment, etc.) and NPS (such as size, shape, surface charge, concentration, etc.) affect physical and chemical processes, which affect their migration and transformation. The migration behavior of NPS in soil has a great influence on the animals, plants and microorganisms. In the context of current research, comparing the relevant literature is a very challenging task, and the reporting data of the relevant features are inadequate, which makes it difficult to describe the differences observed in the study results. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance to colistin has emerged worldwide threatening the efficacy of one of the last-resort antimicrobials used for the treatment of multidrug-resistant Enterobacteriaceae infection in humans. In this study, we investigated the presence of colistin resistance genes (mcr-1, mcr-2, mcr-3) in Escherichia coli strains isolated from poultry and livestock collected between 2004 and 2012 in China. Furthermore, we studied the maintenance and transfer of the mcr-1 gene in E. coli after serial passages. Overall, 2.7% (17/624) of the E. coli isolates were positive for the mcr-1 gene while none were positive for the mcr-2 and mcr-3 genes. The prevalences of mcr-1 were similar in E. coli isolates from chickens (3.2%; 13/404), pigs (0.9%; 1/113) and ducks (6.8%; 3/44) but were absent in isolates from cattle (0/63). The mcr-1 gene was maintained in the E. coli after six passages (equivalent to 60 generations). In vitro transfer of mcr-1 was evident even without colistin selection. Our data indicate the presence of mcr-1 in extraintestinal E. coli from food-producing animals in China, and suggest that high numbers of the mcr-1-positive bacteria in poultry and livestock do not appear to be readily lost after withdrawal of colistin as a food additive. [ABSTRACT FROM AUTHOR]

Background: Chlamydia suis is an important, globally distributed, highly prevalent and diverse obligate intracellular pathogen infecting pigs. To investigate the prevalence and genetic diversity of C. suis in China, 2,137 nasal, conjunctival, and rectal swabs as well as whole blood and lung samples of pigs were collected in 19 regions from ten provinces of China in this study. Results: We report an overall positivity of 62.4% (1,334/2,137) of C. suis following screening by Chlamydia spp. 23S rRNA-based FRET-PCR and high-resolution melting curve analysis and confirmatory sequencing. For C. suis-positive samples, 33.3 % of whole blood and 62.5% of rectal swabs were found to be positive for the C. suis tetR(C) gene, while 13.3% of whole blood and 87.0% of rectal swabs were positive for the C. suis tet(C) gene. Phylogenetic comparison of partial C. suis ompA gene sequences revealed significant genetic diversity in the C. suis strains. This genetic diversity was confirmed by C. suis-specific multilocus sequence typing (MLST), which identified 26 novel sequence types among 27 examined strains. Tanglegrams based on MLST and ompA sequences provided evidence of C. suis recombination amongst the strains analyzed. Conclusions: Genetically highly diverse C. suis strains are exceedingly prevalent in pigs. As it stands, the potential pathogenic effect of C. suis on pig health and production of C. suis remains unclear and will be the subject of further investigations. Further study is also required to address the transmission of C. suis between pigs and the risk of 'spillover' and 'spill-back' of infections to wild animals and humans. [ABSTRACT FROM AUTHOR]

Aims Despite the importance of stem CO2 efflux (Es) in ecosystem carbon cycling and energy balance, little is known about temporal variation in the temperature coefficient (Q10) and sapwood nitrogen concentrations ([N]) and their intrinsic links with Es. The objectives of this study were: (i) to examine the response of Es to temperature in a subalpine region and (ii) to explore the influence of stem diameter and [N] on Es. Also, we will test the hypothesis that (i) Es in trees has thermal acclimation and (ii) Es will be well correlated with diameter at breast height (DBH) and [N]. Methods Here, a horizontally oriented soil chamber technique was applied to measure Es of Abies fabri in two subalpine forest stands in Southwestern China from May to December 2014. We also examined the variability in Es, Q10 and [N] in trees and monitored the relationship between temperature, [N], DBH and Es. Important Findings During the measurement period, Es showed an apparent seasonal trend, following the change in air temperature, increasing from May and peaking in July, then continuously decreasing until December. The mean Es for the growing and dormant seasons were 1.45 and 0.25 μmol.m-2.s-1, respectively, and Es in the mature forest was significantly higher than in the immature forest. The area-based Es was positively correlated with DBH and sapwood width (SW), while volume-based Es showed negative relationship with DBH and SW. Across the five diameter classes, 69.8-89.0% of the variation in Es could be explained by air temperature. The temperature sensitivity (Q10) of Es ranged from 2.98 to 5.61 during the measurement period, with a higher Q10 appearing in the growing season than in the dormant season. There was a significant linear relationship (P < 0.01) between [N] and Es (expressed based on two different units). Additionally, exponential models of Es against [N] and air temperature were applied to estimate Es. [ABSTRACT FROM AUTHOR]

For the 4-DOF (degrees of freedom) trajectory tracking control problem of underwater remotely operated vehicles (ROVs) in the presence of model uncertainties and external disturbances, a novel output feedback fractional-order nonsingular terminal sliding mode control (FO-NTSMC) technique is introduced in light of the equivalent output injection sliding mode observer (SMO) and TSMC principle and fractional calculus technology. The equivalent output injection SMO is applied to reconstruct the full states in finite time. Meanwhile, the FO-NTSMC algorithm, based on a new proposed fractional-order switching manifold, is designed to stabilize the tracking error to equilibrium points in finite time. The corresponding stability analysis of the closed-loop system is presented using the fractional-order version of the Lyapunov stability theory. Comparative numerical simulation results are presented and analyzed to demonstrate the effectiveness of the proposedmethod. Finally, it is noteworthy that the proposed output feedback FO-NTSMC technique can be used to control a broad range of nonlinear second-order dynamical systems in finite time. [ABSTRACT FROM AUTHOR]

High-throughput multiplatform metabolomics experiments are becoming an integral part of clinical and systems biology research. Such methods call for the adoption of robust sample storage and transport formats for small volumes of biofluids. One such format is the dried biofluid spot, which combines small volume requirements with easy portability. Here, we describe ultra high-performance liquid chromatography-mass spectrometry (UHPLC-MS) metabolomics of dried rodent serum, urine, and cerebrospinal fluid spots. An in-vial extraction and UHPLC-MS analysis method was first developed and validated by fingerprinting two test fluids, rat serum and RPMI cell nutrient medium. Data for these extracts were compared in terms of (i) peak area measurements of selected features to assess reproducibility and (ii) total fingerprint variation after data pretreatment. Results showed that percentage peak area variation was found to range between 1.4 and 9.4% relative standard deviation (RSD) for a representative set of molecular features. Upon application of the method to spots bearing serum, urine or cerebrospinal fluid (CSF) from healthy rats and mice, a total of 1?182 and 2?309 reproducible molecular features were obtained in positive and negative ionization modes, respectively, of which 610 (positive) and 991 (negative) were found in both rats and mice. Feature matching was used to detect similarities and differences between biofluids, with the biggest overlap found between fingerprints obtained in urine and CSF. Our results thus demonstrate the potential of such direct fingerprinting of dried biofluid spots as a viable alternative to the use of small (10-15 μL) volumes of neat biofluids in animal studies. [ABSTRACT FROM AUTHOR]

The sense of touch plays a critical role in traditional open surgeries since it could provide tactile feedback to surgeons and is also used to acquire intrinsic properties of tissues through palpation. However, it is partially or completely lost in most existing robot-assisted minimally invasive surgeries. To solve this problem, a miniature tactile sensor with diameter less than 8 mm suitable for catheter robot-based tissue hardness palpation is presented in this paper. The stringent size constraint of minimally invasive surgery (MIS) is met by a unique spiral shape as well as a vertically configured piezoelectric transducer. The spiral shape also helps it achieve a low operating frequency suitable for testing biological tissues. The relationship between electrical impedance of the sensor and mechanical impedance of a load is derived based on the transduction matrix model, which forms the basis of the unique simultaneous actuation and sensing (SAS) technique. As a result, hardness of the load could be sensed from the sensor’s electrical impedance by extracting the resonant frequency, with simple instrumentation. The proposed sensor and SAS technique are verified numerically on a finite element model and experimentally on a prototype. After properly choosing the vibration mode and operating frequency range, the sensor is able to perform hardness sensing in a wide range of 0–1.7 MPa. In addition, both simulation and experiment results indicate that the sensor has high sensitivity and low variance in the low-hardness region, and relatively lower sensitivity and higher variance in the high-hardness region, suggesting that the sensor can be used in two different sensing modes (quantitative measurement and qualitative classification) in the two regions, respectively. An ex vivo experiment confirms that the sensor could detect the presence, shape and location of an embedded lump from spatial distribution of tissue hardness acquired through grid-based palpation, followed by an improved k-means clustering algorithm. Compared with traditional hardness sensors, this tactile sensor is developed with a unique spiral shape which reduces the operating frequency for enhancing the interaction with biological tissues while keeps the overall size of the sensor as small as possible. And the proposed unique simultaneous actuation and electrical impedance sensing mode helps simplify the instrumentation, making it easier to integrate the sensor into MIS equipment. [ABSTRACT FROM AUTHOR]

This paper presents a novel piezoelectric tactile sensor for tissue hardness sensing, featuring online tunable sensing performance (resonant frequency, sensitivity, measurement range) through varying its mechanical impedance. The variable-impedance mechanism is achieved with a unique double-cantilever structure, which also enables the sensor to operate at a low frequency suitable for testing biological tissues. A simultaneous actuation and sensing technique is used which allows detecting resonant frequency from electrical impedance of the piezoelectric actuator without using additional motion sensors, therefore simplifies the sensor’s structure and instrumentation. The basic working principle and the variable-impedance method for performance tuning are explained mathematically and verified by numerical and experimental studies. The test results on a prototype show that it has an operating frequency (<300 Hz) much better than those in the literature. With the variable-impedance mechanism, sensitivity improvement ratios of 1.7, 2.6 and 3.8 times are achieved in three test ranges. And measurement range improvement ratio of 6.2 times is achieved. Ex vivo experiment confirms its effectiveness in detecting embedded lump. The proposed sensor can find wide applications in robotics, biomedical engineering, aerospace, etc, and may eventually inspire the designs of a new class of tactile sensors with online performance tuning capability. [ABSTRACT FROM AUTHOR]

Isthmin-1 （ISM1） belongs to the Isthmin gene family. It is expressed in various tissues and has multiple biological functions. ISM1 is involved in growth and development， metabolism， immunity， tumorigenesis and other physiological and pathological processes， which is associated with a variety of lung diseases， including acute respiratory distress syndrome， chronic obstructive pulmonary disease and pulmonary fibrosis， etc. In this article， the structure， biological function of ISM1 and its role in pulmonary diseases were reviewed， aiming to provide a theoretical basis for the diagnosis and treatment of ISM1-related diseases.

In order to understand the mechanism of cavity shedding and evolution, turbulent cavitating flows of the twisted hydrofoil were numerically investigated using the k-ε turbulence model and the ZGB cavitation model. The results of the numerical calculation and the experimental method are basically consistent, which confirms the feasibility of the numerical calculation model. This study has obtained the following conclusions. Firstly, the cavity shedding can be summarized into six stages, and the cavity shape, pressure and velocity field at different stages are displayed, analyzed and compared in detail. Secondly, the shedding of cavity and its evolution are mainly caused by the re-entrant jet and side-entrant jet, in which the former provides the kinetic energy and the latter plays the role of guiding the direction. Thirdly, under the convective shearing action of the re-entrant jet and the main flow, a strong vortex located in the mid-back edge of the hydrofoil is formed, which promotes the transformation of the cavity shape into a U-shaped structure. [ABSTRACT FROM AUTHOR]

The fungus Puccinia striiformis f. sp. tritici (Pst) is an important threat to wheat production because it can cause wheat stripe rust. The present study aimed to identify new stripe rust resistance genes and to provide a theoretical and practical basis for breeding wheat varieties with broad spectrum, stable, and durable resistance. Wheat leaves inoculated with wheat stripe rust fungus Chinese yellow rust 34 were collected at different time points for transcriptomic analysis based on the wheat stripe rust susceptible varieties AVOCET S (AVS) and AVSYr15NIL [near-isogenic line (NIL) derived from AVS]. The results showed that the number of upregulated genes in the two varieties was 294, 364, 398, and 604, and the number of downregulated genes was 520, 178, 570, and 345 on the 1st, 3rd, 5th, and 7th days post inoculation, respectively. Gene Ontology and Kyoto Encyclopedia of Gene and Genomes enrichment analyses found enrichment of differentially expressed genes in the peroxisome proliferators-activated receptor signaling pathways, plant-pathogen interaction, and styrene acrylic acid biosynthesis that encoded protein kinases, signal transduction, transcription factors, and functional protein components. Differentially expressed genes were randomly selected for quantitative reverse transcription PCR analysis, and the change trend was the same as in the transcriptome data. The results of this study suggest that genes in AVSYr15NIL related to the stripe rust response could be valuable for understanding the mechanisms involved in stripe rust resistance. [ABSTRACT FROM AUTHOR]

The gas-particle two-phase flow in a multistep dust collector has been numerically analysed for the improvement of particle separation efficiency under several typical industrial conditions. Moreover, the calculated results are validated by experiments with a maximum error emax = 4.6%. The results indicate the influence of the geometrical dimensions of the multistep dust collector on particle separation efficiency and pressure drop. The present study proposes an effective approach to optimize a dust collector, which can improve particle separation efficiency at low cost and in a short development cycle. [ABSTRACT FROM AUTHOR]