21 research outputs found

    Application of a tracing experiment in the prediction of water and mud inrush in the Wantan Tunnel

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    Taking the Wantan Tunnel of Yilai Highway as the study case, the average water inflow and the water inflow in the wet season of the tunnel are calculated through field investigation, groundwater tracer experiment, groundwater flow monitoring, and atmospheric rainfall infiltration method. Meanwhile, the realistic failure process analysis(RFPA) is used to analyze the possibility of tunnel water inrush is judged. The results of field survey and tracer test show that the karst pipeline of Wantan Tunnel is a multi-branched, mixed-type karst pipeline with complicated hydrogeological conditions. The water inflow in wet season is about 4.6 times of the average tunnel water inflow. Mud failure will go through the stages of crack initiation, crack expansion, further crack expansion, and through-through failure. At the same time, when the water flow at the karst pipeline reaches about 2.7 to 3.5 times the initial value (37 248 m3/d), water gushing and mud inrush damage will occur, that is, when the flow of water outlet 2 reaches 10 000 to 13 000 m3/d, There is a very high risk of water and mud gushing in the Wantan Tunnel

    Lactoferrin/Calcium Phosphate-Modified Porous Ti by Biomimetic Mineralization: Effective Infection Prevention and Excellent Osteoinduction

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    The surface modification of titanium (Ti) can enhance the osseointegration and antibacterial properties of implants. In this study, we modified porous Ti discs with calcium phosphate (CaP) and different concentrations of Lactoferrin (LF) by biomimetic mineralization and examined their antibacterial effects and osteogenic bioactivity. Firstly, scanning electron microscopy (SEM), the fluorescent tracing method, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and the releasing kinetics of LF were utilized to characterize the modified Ti surface. Then, the antibacterial properties against S. sanguis and S. aureus were investigated. Finally, in vitro cytological examination was performed, including evaluations of cell adhesion, cell differentiation, extracellular matrix mineralization, and cytotoxicity. The results showed that the porous Ti discs were successfully modified with CaP and LF, and that the LF-M group (200 μg/mL LF in simulated body fluid) could mildly release LF under control. Further, the LF-M group could effectively inhibit the adhesion and proliferation of S. sanguis and S. aureus and enhance the osteogenic differentiation in vitro with a good biocompatibility. Consequently, LF-M-modified Ti may have potential applications in the field of dental implants to promote osseointegration and prevent the occurrence of peri-implantitis

    Friction and neuroimaging of active and passive tactile touch

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    Abstract Two types of exploratory touch including active sliding and passive sliding are usually encountered in the daily life. The friction behavior of the human finger against the surface of objects is important in tactile perception. The neural mechanisms correlating to tribological behavior are not fully understood. This study investigated the tactile response of active and passive finger friction characterized with functional near-infrared spectroscopy (fNIRS). The friction test and fNIRS test were performed simultaneously using the tactile stimulus of polytetrafluoroethylene (PTFE) specimens. Results showed that the sliding modes did not obviously influence the friction property of skin. While three cortex regions were activated in the prefrontal cortex (PFC), showing a higher activation level of passive sliding. This revealed that the tribological performance was not a simple parameter to affect tactile perception, and the difference in cortical hemodynamic activity of active and passive touch was also recognised. The movement-related blood flow changes revealed the role of PFC in integrating tactile sensation although there was no estimation task on roughness perception

    Redistribution of <i>Qiongzhuea tumidinoda</i> in Southwest China under Climate Change: A Study from 1987 to 2012

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    Qiongzhuea tumidinoda stands out as an endemic bamboo species of significant conservation importance in Southwest China, particularly in the upper reaches of the Yangtze River. It holds a pivotal role in poverty alleviation through the commercialization of its wood and bamboo shoots. However, the suitable area of this species is undergoing rapid changes due to climate change, resulting in species redistribution and potential losses for bamboo farmers. We utilized 209 presence records and 25 environmental variables from 1987 to 2012 to predict the potentially suitable habitats for Q. tumidinoda using MaxEnt (version 3.4.1), ArcGIS (version 10.8.2), and R (4.3.3). We rigorously screened the recorded data for reliability and accuracy through expert consultations and observer interviews. We performed pre-processing to select the variables with high contributions for modeling, and 11 variables were selected for the final modeling. Our findings reveal that the top three most influential variables associated with Q. tumidinoda’s distribution were the mean monthly potential evapotranspiration (Pet), annual range of air temperatures (Bio7), and mean diurnal air temperature range (Bio2), and the rates of contributions from 1987 to 2012 were 4.8333, 3.5833, and 1.7000. There was a southeastward shift and an elevation increase in the potentially suitable habitats for Q. tumidinoda. The area of potentially suitable habitats in the study region exhibited fluctuating growth, expanding from 3063.42 km2 to 7054.38 km2. The mean monthly potential evapotranspiration (Pet) emerged as a critical determinant shaping the distribution of potentially suitable habitats for Q. tumidinoda. Our study sheds light on the response of Q. tumidinoda to climate change, offering valuable insights for the development and management of plantation industries associated with this species. In the future, to enhance prediction accuracy, researchers could equally consider both organic and inorganic environmental variables. For better preservation of environment and development, Q. tumidinoda could be introduced into nature restoration projects in areas with a suitable habitat or as a commodity that participates in forest carbon sink trading

    Magnetic scaffold constructing by micro-injection for bone tissue engineering under static magnetic field

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    The utilization of static magnetic fields in conjunction with tissue engineering scaffolds has demonstrated significant potential in the restoration of bone defects. However, previous techniques used for fabricating magnetic tissue engineering scaffolds have shown certain shortcomings that require further investigation. In this study, a series of scaffolds made from a combination of polylactic acid (PLA), polycaprolactone (PCL), and iron tetraoxide (Fe3O4) nanoparticles were designed and prepared using the microinjection molding technique. The composite scaffolds, which were doped with nanoparticles and fabricated through microinjection, exhibited exceptional physicochemical properties and biocompatibility. Additionally, the PLA/PCL/Fe3O4 scaffolds were found to promote the proliferation and adhesion of bone marrow cells (BMSCs) under relatively low magnetic fields (25–30 mT). These findings suggest that PLA/PCL/Fe3O4 scaffolds hold great potential for use in bone tissue engineering applications

    Topology Universality and Dissimilarity in a Class of Scale-Free Networks

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    <div><p>We study the effect of subtle changes on the evolution in the scale-free (SF) networks. Three extended models are evolved based on competition and inner anti-preferential deletion in growth and preferential attachment processes. By nonlinear and dynamic controlling on randomness and determinacy, three models can self-organize into scale-free networks, and diverse scaling exponents appear. Moreover, the model with more determinacy has more stringent parameter control than randomness, especially in the edge deletion. Our results suggest that the nature of the topology universality and dissimilarity in SF networks may be the subtle changes of randomness and determinacy.</p></div

    (a)—(c) With different conditions and parameters to compare the numerical simulation and the theoretical prediction of the degree distribution <i>P</i>(<i>k</i>) for the model R.

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    <p>(a) With the condition <i>q</i> = <i>n</i> and after time <i>t</i> = 1000, three groups of the parameters are , <i>m</i><sub>0</sub> = <i>m</i> = 3, <i>q</i> = <i>n</i> = 2; , <i>m</i><sub>0</sub> = <i>m</i> = 3, <i>q</i> = <i>n</i> = 1; , <i>m</i><sub>0</sub> = <i>m</i> = 3, <i>q</i> = <i>n</i> = 2. Blue, red and black solid lines stand for the theoretical degree distribution <i>P</i>(<i>k</i>); red plus, black asterisk and blue diamond stand for the numerical simulation of degree distribution <i>P</i>(<i>k</i>) of three groups respectively. (b) With the condition <i>q</i> < <i>n</i> and after time <i>t</i> = 1000, three groups of the parameters are , <i>m</i><sub>0</sub> = <i>m</i> = 8, <i>n</i> = 2, <i>q</i> = 1; , <i>m</i><sub>0</sub> = <i>m</i> = 4, <i>n</i> = 3, <i>q</i> = 1; , <i>m</i><sub>0</sub> = <i>m</i> = 8, <i>n</i> = 4, <i>q</i> = 1. Blue, red and black solid lines stand for the theoretical degree distribution <i>P</i>(<i>k</i>); red plus, black asterisk and blue diamond stand for the numerical simulation of degree distribution <i>P</i>(<i>k</i>) of three groups respectively. (c) With the condition <i>q</i> > <i>n</i> and after time <i>t</i> = 1000, two groups of the parameters are , <i>m</i><sub>0</sub> = <i>m</i> = 4, <i>n</i> = 1, <i>q</i> = 3; , <i>m</i><sub>0</sub> = <i>m</i> = 3, <i>n</i> = 1, <i>q</i> = 3. Blue and red solid lines stand for the theoretical degree distribution <i>P</i>(<i>k</i>); red plus and black asterisk stand for the numerical simulation of degree distribution <i>P</i>(<i>k</i>) of two groups respectively. (d) The numerical simulations of degree distribution <i>P</i>(<i>k</i>) with different competition abilities <i>η</i> and the static parameters <i>C</i> = 2, <i>m</i> = 3, <i>n</i> = 2, <i>q</i> = 1.</p

    Environmental triggers of autoimmunity: The association between bisphenol analogues and systemic lupus erythematosus

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    The aim of this research was to examine the correlation between the exposure to bisphenol analogues (BPs), such as bisphenol A (BPA), bisphenol F (BPF), and bisphenol S (BPS), and the risk of developing systemic lupus erythematosus (SLE). Ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) was utilized to measure the levels of BPA, BPF, and BPS in the urine of 168 female participants diagnosed with SLE and 175 female participants who were deemed healthy controls. Logistic regression models were utilized to assess the connections between levels of bisphenol and the risk of SLE. The findings indicated that levels of BPA and BPF in the urine of individuals with SLE were markedly elevated compared to those in the control group. Higher exposure to BPA and BPF exhibited positive dose-response relationships with increased SLE risk. No significant associations were identified between BPS and the risk of SLE. These findings suggest exposure to BPA and BPF may be implicated as novel environmental triggers in the development of autoimmunity such as SLE. The significantly increased levels of these bisphenol analogues detected in SLE patients versus healthy controls, along with the associations between higher exposures and elevated SLE risk, which offers crucial hints for comprehending how endocrine-disrupting substances contribute to the genesis of autoimmune illnesses. Further research using robust longitudinal assessments of bisphenol analogue exposures is warranted to corroborate these epidemiological findings. Overall, this study highlights potential environmental risk factors for SLE while calling for additional investigation into the impact of bisphenol exposures on autoimmunity development

    Chemical Sensing Systems that Utilize Soft Electronics on Thin Elastomeric Substrates with Open Cellular Designs

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    A collection of materials and device architectures are introduced for thin, stretchable arrays of ion sensors that mount on open cellular substrates to facilitate solution exchange for use in biointegrated electronics. The results include integration strategies and studies of fundamental characteristics in chemical sensing and mechanical response. The latter involves experimental measurements and theoretical simulations that establish important considerations in the design of low modulus, stretchable properties in cellular substrates, and in the realization of advanced capabilities in spatiotemporal mapping of chemicals' gradients. As the chemical composition of extracellular fluids contains valuable information related to biological function, the concepts introduced here have potential utility across a range of skin- and internal-organ-integrated electronics where soft mechanics, fluidic permeability, and advanced chemical sensing capabilities are key requirements. © 2017 WILEY-VCH Verlag GmbH &amp; Co. KGaA, WeinheimFALS

    The Sigma Factor AlgU Regulates Exopolysaccharide Production and Nitrogen-Fixing Biofilm Formation by Directly Activating the Transcription of pslA in Pseudomonas stutzeri A1501

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    Pseudomonas stutzeri A1501, a plant-associated diazotrophic bacterium, prefers to conform to a nitrogen-fixing biofilm state under nitrogen-deficient conditions. The extracytoplasmic function (ECF) sigma factor AlgU is reported to play key roles in exopolysaccharide (EPS) production and biofilm formation in the Pseudomonas genus; however, the function of AlgU in P. stutzeri A1501 is still unclear. In this work, we mainly investigated the role of algU in EPS production, biofilm formation and nitrogenase activity in A1501. The algU mutant &Delta;algU showed a dramatic decrease both in the EPS production and the biofilm formation capabilities. In addition, the biofilm-based nitrogenase activity was reduced by 81.4% in the &Delta;algU mutant. The transcriptional level of pslA, a key Psl-like (a major EPS in A1501) synthesis-related gene, was almost completely inhibited in the algU mutant and was upregulated by 2.8-fold in the algU-overexpressing strain. A predicted AlgU-binding site was identified in the promoter region of pslA. The DNase I footprinting assays indicated that AlgU could directly bind to the pslA promoter, and &beta;-galactosidase activity analysis further revealed mutations of the AlgU-binding boxes drastically reduced the transcriptional activity of the pslA promoter; moreover, we also demonstrated that AlgU was positively regulated by RpoN at the transcriptional level and negatively regulated by the RNA-binding protein RsmA at the posttranscriptional level. Taken together, these data suggest that AlgU promotes EPS production and nitrogen-fixing biofilm formation by directly activating the transcription of pslA, and the expression of AlgU is controlled by RpoN and RsmA at different regulatory levels
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