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Additional file 1: Table S1. Comparison of taxonomic and functional β-diversity between and within treatments. Table S2. Effects of N deposition on microbial taxonomic and functional diversity, as assessed by Shannon index. Table S3. Significantly changed representative OTUs calculated by difference analyses. Table S4. Topological properties of microbial functional gene networks. Table S5. Summary of soil and vegetation attributes in control and N deposited samples. Table S6. Mantel tests for correlations between a range of environmental attributes and quantitative measures of microbial community dissimilarity. Fig. S1. Comparison of the percentage change by N deposition for (a) microbial phyla; (b) N cycling genes; and (c) C cycling genes between using 32 and 4 samples as biological replicates. Fig. S2. The percentage change in relative abundances of microbial class induced by long-term N deposition. Asterisks indicate significant differences. *, P < 0.050; **, P < 0.010. Fig. S3. The percentage change in the relative abundance of major microbial genera induced by long-term N deposition treatment. All selected genera are significantly changed by N deposition treatment as calculated by the response ratio analysis. Fig. S4. The percentage change in the relative abundance of genes associated with C fixation induced by N deposition, calculated as 100*(( mean value in N deposited samples/mean value in control samples) – 1). Mean values and standard deviations are presented. Asterisks indicate significant differences. *, P < 0.050; **, P < 0.010. The numbers in the figure represent the pathways of C fixation. (i) 3-hydroxypropionate bicycle, (ii) Bacterial microcompartments, (iii) Calvin cycle, and (iv) Reductive tricarboxylic acid cycle. Fig. S5. The percentage change in the relative abundance of genes associated with methane and phosphorus cycling genes induced by N deposition, calculated as 100*((mean value in N deposited samples/mean value in control samples) – 1). Mean values and standard deviations are presented. Asterisks indicate significant differences. *, P < 0.050; **, P < 0.010. Fig. S6. N deposition effects on amoA gene. The relative abundance of amoA is presented as the signal intensity difference between control and N deposited samples. Error bars represent standard errors. Blue bars represent genes derived from archaea (AOA), and pink bars represent genes derived from bacteria (AOB). Asterisks indicate significant differences. *, P < 0.050; **, P < 0.010.

Porous CeO2/Au/CeO2 nanorod catalyst has been synthesized by using Ce-MOF as sacrificial template. The preparation involves several sequential steps as follows: 1) synthesis of Ce-MOF, 2) anchoring of Au on Ce-MOF, 3) depositing of tiny CeO2 particles on Ce-MOF/Au through hydrothermal reaction; 4) pyrolysis of Ce-MOF to prepare the inner CeO2 support and obtain grain growth of the outmost CeO2 particles. The TEM and XPS result demonstrated similar chemical properties of CeO2 derived from pyrolysis of Ce-MOF template and growth of tiny CeO2 grains. Moreover, Au nanoparticles can be effectively protected from growth of particle size by the surrounding CeO2 particles. The CeO2/Au/CeO2 catalyst exhibits a remarkable higher catalytic activity in comparison with CeO2/Au counterparts toward reduction of 4-nitrophenol to 4-aminophenol by NaBH4.

A novel porous CeO2/Au@SiO2 nanocatalyst with a hollow tube structure was fabricated by using a metal–organic framework as the precursor and sacrificial template. The structure of the nanocatalyst was characterized in detail by TEM, XRD, N2 physical adsorption and XPS. Au nanoparticles with a mean diameter of 4.8 nm were loaded on the Ce-MOF surface because of the strong chemical affinity between Au NPs and carboxylate ions of the Ce-MOF. The pyrolysis of Ce-MOF gave rise to the formation of a mesoporous CeO2 hollow tube without alteration of the Au size due to the encapsulation by a SiO2 shell. The as-prepared CeO2/Au@SiO2 nanocatalyst exhibited excellent catalytic activity towards 4-nitrophenol reduction. The superior catalytic activity was attributed to the unique and small size of the Au nanoparticles, the mesoporous structure and the strong interaction between the CeO2 and Au nanoparticles.

As the second-largest terrestrial carbon (C) flux, soil respiration (RS) has been stimulated by climate warming. However, the magnitude and dynamics of suchstimulations of soil respiration are highly uncertain at the global scale, undermining our confidence in future climate projections. Here, we present an analysis of global RS observations from 1987-2016. RS increased (P

This paper evaluates the reliability of lumber, accounting for the duration-of-load (DOL) effect under different load profiles based on a multimodel Bayesian approach. Three individual DOL models previously used for reliability assessment are considered: the US model, the Canadian model, and the Gamma process model. Procedures for stochastic generation of residential, snow, and wind loads are also described. We propose Bayesian model-averaging (BMA) as a method for combining the reliability estimates of individual models under a given load profile that coherently accounts for statistical uncertainty in the choice of model and parameter values. The method is applied to the analysis of a Hemlock experimental dataset, where the BMA results are illustrated via estimated reliability indices together with 95% interval bands., Comment: 15 pages, 2 figures

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An array of isosceles triangular microchannels with sidewalls inclined at 54.7° were fabricated by the wet etching method. The condensation of water and ethanol binary mixtures was visualized with additional measurements to investigate the condensation flow patterns in the silicon microchannels with hydraulic diameters of approximately 155 μm. The visualization study indicated that the flow patterns were influenced by the inlet ethanol concentration and the mass flux. Annular, injection, droplet-injection and bubble flow patterns were observed along the channels. The condensation instability effects were stronger with increased equivalent surface free energy differences. The increasing equivalent surface free energy differences caused droplets to form in the microchannel that moved from the condensing surface to the top corner due to the Marangoni effect, which led to fluctuating flow patterns. The frequency of the injection flow increased with increasing Rev and input ethanol concentration. The mass flux and the steam quality during condensation were measured at various locations in the experiments. Two phase flow pattern maps were developed for various inlet ethanol concentrations.

The source rock quality, organic pore structure, occurrence state and sealing mechanisms of shale gas in the Ordovician Wufeng – SilurianLongmaxi Formation (O3w-S1l), Fuling region, Sichuan Basin were studied using a series of techniques including ultra-microscopic organic maceral identification, FIB-SEM, high temperature/pressure isothermal adsorption and isotopic age dating of noble gas. The results show that: (1) O3w-S1l organic-rich shale was mainly formed in a sedimentary environment with high productivity in surface water and hypoxia in bottom water, which can be divided into two sections according to TOC. The lower section (TOC≥3%) is mainly composed of graptolite, phytoplankton, acritarch, bacteria and solid bitumen. Graptolite is the main contributor to TOC, but the shale gas is mainly derived from hydrogen-rich organic matter such as phytoplankton, acritarch and pyrolysis of liquid hydrocarbons produced by hydrogen-rich organic matter. (2) Organic pores, as principal reservoir space for shale gas, exist in hydrogen-rich organic matter and solid bitumen. The graptolites and plenty of other organic matter stacking distribution in lamina provide both reservoir space for supplement and effective pathways of connected pores for shale gas. (3) Shale gas in Fuling region is in supercritical state and dominated by free gas. The match of formation time of closed shale gas system and gas-generation peak, as well as slight alteration degree of sealing conditions in the later stage, are key factors controlling the retention and accumulation of shale gas in the regions with high thermal maturity and complex tectonic background. Adsorption, capillary sealing and slow diffusion of shale are the main microscopic mechanisms for the retention and accumulation of shale gas. It thus can be seen that the generation and accumulation of marine shale gas with high thermal maturity in complex structure areas is controlled jointly by anoxic depositional environment, excellent hydrocarbon rock quality, superior reservoir space and favorable sealing conditions. Key words: Sichuan Basin, Fuling gas field, shale gas, hydrocarbon-forming organisms, reservoir space, occurrence state, sealing mechanism

Nitrogen (N) deposition is a component of global change that has considerable impact on belowground carbon (C) dynamics. Plant growth stimulation and alterations of fungal community composition and functions are the main mechanisms driving soil C gains following N deposition in N-limited temperate forests. In N-rich tropical forests, however, N deposition generally has minor effects on plant growth; consequently, C storage in soil may strongly depend on the microbial processes that drive litter and soil organic matter decomposition. Here, we investigated how microbial functions in old-growth tropical forest soil responded to 13years of N addition at four rates: 0 (Control), 50 (Low-N), 100 (Medium-N), and 150 (High-N) kgNha-1 year-1 . Soil organic carbon (SOC) content increased under High-N, corresponding to a 33% decrease in CO2 efflux, and reductions in relative abundances of bacteria as well as genes responsible for cellulose and chitin degradation. A 113% increase in N2 O emission was positively correlated with soil acidification and an increase in the relative abundances of denitrification genes (narG and norB). Soil acidification induced by N addition decreased available P concentrations, and was associated with reductions in the relative abundance of phytase. The decreased relative abundance of bacteria and key functional gene groups for C degradation were related to slower SOC decomposition, indicating the key mechanisms driving SOC accumulation in the tropical forest soil subjected to High-N addition. However, changes in microbial functional groups associated with N and P cycling led to coincidentally large increases in N2 O emissions, and exacerbated soil P deficiency. These two factors partially offset the perceived beneficial effects of N addition on SOC storage in tropical forest soils. These findings suggest a potential to incorporate microbial community and functions into Earth system models considering their effects on greenhouse gas emission, biogeochemical processes, and biodiversity of tropical ecosystems.

Aim: The factors driving microbial community β-diversity (variation in composition) at different spatial scales yield fundamental insights into the mechanisms that maintain ecosystem biodiversity, which as yet are uncertain. Here, we explore whether spatial scale-dependent patterns of β-diversity vary between microbial functional groups and bacterial taxa (i.e., diazotrophic and bacterial communities) across local to regional scales (from metres to hundreds of kilometres). Location: Eastern China. Time period: October and November 2015. Major taxa studied: Diazotrophic and bacterial communities. Methods We use two complementary statistical tools to unveil biotic mechanisms (i.e., species association) underlying variation in β-diversity of diazotrophic and bacterial communities. We examined distance–decay slopes of both communities at the local (1–113m), meso- (3.4–39km) and regional (103–668km) scales. We used an environmentally constrained checkerboard score and topological features of association networks as indices of species association. We then calculated contributions of species association, abiotic factors and geographical distance to explain community β-diversity. The scale-dependent distance–decay relationships were also examined in ubiquitous (high occupancy across samples) and endemic communities of diazotrophs and bacteria. Results Diazotrophs displayed steeper distance–decay slopes than bacteria, suggesting that the β-diversity of diazotrophic communities was more variable. The distance–decay slopes were dependent on spatial scales in both communities, owing to different contributions of geographical distance, abiotic factors and species association at three spatial scales. Intriguingly, species association was greater and contributed more to community β-diversity than other forces at the local scale, implying that species association could greatly alter community structures. Main conclusions Drivers of diazotrophic and bacterial community β-diversity depended on spatial scales, resulting in different distance–decay patterns. Moreover, this was the first study to use two methods to demonstrate that species association played important, but as yet unrecognized, roles in driving spatial scale-dependent β-diversity.

Mild disturbances are prevalent in the environment, which may not be easily notable but could have considerable ecological consequences over prolonged periods. To evaluate this, a field study was designed to examine the effects of very light-intensity lamb grazing on grassland soil microbiomes with different soil backgrounds. No significant change (P > 0.05) was observed in any vegetation and soil variables. Nonetheless, hundreds of microbial functional gene families, but not bacterial taxonomy, were significantly (P

Both fungi and bacteria play essential roles in regulating soil carbon cycling. To predict future carbon stability, it is imperative to understand their responses to environmental changes, which is subject to large uncertainty. As current global warming is causing range shifts toward higher latitudes, we conducted three reciprocal soil transplantation experiments over large transects in 2005 to simulate abrupt climate changes. Six years after soil transplantation, fungal biomass of transplanted soils showed a general pattern of changes from donor sites to destination, which were more obvious in bare fallow soils than in maize cropped soils. Strikingly, fungal community compositions were clustered by sites, demonstrating that fungi of transplanted soils acclimatized to the destination environment. Several fungal taxa displayed sharp changes in relative abundance, including Podospora, Chaetomium, Mortierella and Phialemonium. In contrast, bacterial communities remained largely unchanged. Consistent with the important role of fungi in affecting soil carbon cycling, 8.1%-10.0% of fungal genes encoding carbon-decomposing enzymes were significantly (p

International audience; Microorganisms in wastewater treatment plants (WWTPs) are essential for water purification to protect public and environmental health. However, the diversity of microorganisms and the factors that control it are poorly understood. Using a systematic global-sampling effort, we analysed the 16S ribosomal RNA gene sequences from ~1,200 activated sludge samples taken from 269 WWTPs in 23 countries on 6 continents. Our analyses revealed that the global activated sludge bacterial communities contain ~1 billion bacterial phylotypes with a Poisson lognormal diversity distribution. Despite this high diversity, activated sludge has a small, global core bacterial community (n = 28 operational taxonomic units) that is strongly linked to activated sludge performance. Meta-analyses with global datasets associate the activated sludge microbiomes most closely to freshwater populations. In contrast to macroorganism diversity, activated sludge bacterial communities show no latitudinal gradient. Furthermore, their spatial turnover is scale-dependent and appears to be largely driven by stochastic processes (dispersal and drift), although deterministic factors (temperature and organic input) are also important. Our findings enhance our mechanistic understanding of the global diversity and biogeography of activated sludge bacterial communities within a theoretical ecology framework and have important implications for microbial ecology and wastewater treatment processes.

Accurate climate projections require an understanding of the effects of warming on ecological communities and the underlying mechanisms that drive them1–3. However, little is known about the effects of climate warming on the succession of microbial communities4,5. Here we examined the temporal succession of soil microbes in a long-term climate change experiment at a tall-grass prairie ecosystem. Experimental warming was found to significantly alter the community structure of bacteria and fungi. By determining the time-decay relationships and the paired differences of microbial communities under warming and ambient conditions, experimental warming was shown to lead to increasingly divergent succession of the soil microbial communities, with possibly higher impacts on fungi than bacteria. Variation partition- and null model-based analyses indicate that stochastic processes played larger roles than deterministic ones in explaining microbial community taxonomic and phylogenetic compositions. However, in warmed soils, the relative importance of stochastic processes decreased over time, indicating a potential deterministic environmental filtering elicited by warming. Although successional trajectories of microbial communities are difficult to predict under future climate change scenarios, their composition and structure are projected to be less variable due to warming-driven selection.

Eutrophication and climate warming, induced by anthropogenic activities, are simultaneously occurring worldwide and jointly affecting soil carbon stability. Therefore, it is of great interest to examine whether and how they interactively affect soil microbial community, a major soil carbon driver. Here, we showed that climate warming, simulated by southward transferring Mollisol soil in agricultural ecosystems from the cold temperate climate zone (N) to warm temperate climate (C) and subtropical climate zone (S), decreased soil organic matter (SOM) by 6%-12%. In contrast, amendment with nitrogen, phosphorus and potassium enhanced plant biomass by 97% and SOM by 6% at the N site, thus stimulating copiotrophic taxa but reducing oligotrophic taxa in relative abundance. However, microbial responses to nutrient amendment were overridden by soil transfer in that nutrient amendment had little effect at the C site but increased recalcitrant carbon-degrading fungal Agaricomycetes and Microbotryomycetes taxa derived from Basidiomycota by 4-17 folds and recalcitrant carbon-degrading genes by 23%-40% at the S site, implying a possible priming effect. Consequently, SOM at the S site was not increased by nutrient amendment despite increased plant biomass by 108%. Collectively, we demonstrate that soil transfer to warmer regions overrides microbial responses to nutrient amendment and weakens soil carbon sequestration.

Permafrost soil in high latitude tundra is one of the largest terrestrial carbon (C) stocks and is highly sensitive to climate warming. Understanding microbial responses to warming-induced environmental changes is critical to evaluating their influences on soil biogeochemical cycles. In this study, a functional gene array (i.e., geochip 4.2) was used to analyze the functional capacities of soil microbial communities collected from a naturally degrading permafrost region in Central Alaska. Varied thaw history was reported to be the main driver of soil and plant differences across a gradient of minimally, moderately, and extensively thawed sites. Compared with the minimally thawed site, the number of detected functional gene probes across the 15-65cm depth profile at the moderately and extensively thawed sites decreased by 25% and 5%, while the community functional gene β-diversity increased by 34% and 45%, respectively, revealing decreased functional gene richness but increased community heterogeneity along the thaw progression. Particularly, the moderately thawed site contained microbial communities with the highest abundances of many genes involved in prokaryotic C degradation, ammonification, and nitrification processes, but lower abundances of fungal C decomposition and anaerobic-related genes. Significant correlations were observed between functional gene abundance and vascular plant primary productivity, suggesting that plant growth and species composition could be co-evolving traits together with microbial community composition. Altogether, this study reveals the complex responses of microbial functional potentials to thaw-related soil and plant changes and provides information on potential microbially mediated biogeochemical cycles in tundra ecosystems.

Aeolian soil erosion and deposition have worldwide impacts on agriculture, air quality and public health. However, ecosystem responses to soil erosion and deposition remain largely unclear in regard to microorganisms, which are the crucial drivers of biogeochemical cycles. Using integrated metagenomics technologies, we analysed microbial communities subjected to simulated soil erosion and deposition in a semiarid grassland of Inner Mongolia, China. As expected, soil total organic carbon and plant coverage were decreased by soil erosion, and soil dissolved organic carbon (DOC) was increased by soil deposition, demonstrating that field simulation was reliable. Soil microbial communities were altered (p

Rapid climate change and intensified human activities have resulted in water table lowering (WTL) and enhanced nitrogen (N) deposition in Tibetan alpine wetlands. These changes may alter the magnitude and direction of greenhouse gas (GHG) emissions, affecting the climate impact of these fragile ecosystems. We conducted a mesocosm experiment combined with a metagenomics approach (GeoChip 5.0) to elucidate the effects of WTL (-20cm relative to control) and N deposition (30kg N ha-1 yr-1 ) on carbon dioxide (CO2 ), methane (CH4 ) and nitrous oxide (N2 O) fluxes as well as the underlying mechanisms. Our results showed that WTL reduced CH4 emissions by 57.4% averaged over three growing seasons compared with no-WTL plots, but had no significant effect on net CO2 uptake or N2 O flux. N deposition increased net CO2 uptake by 25.2% in comparison with no-N deposition plots and turned the mesocosms from N2 O sinks to N2 O sources, but had little influence on CH4 emissions. The interactions between WTL and N deposition were not detected in all GHG emissions. As a result, WTL and N deposition both reduced the global warming potential (GWP) of growing season GHG budgets on a 100-year time horizon, but via different mechanisms. WTL reduced GWP from 337.3 to -480.1g CO2 -eq m-2 mostly because of decreased CH4 emissions, while N deposition reduced GWP from 21.0 to -163.8g CO2 -eq m-2 , mainly owing to increased net CO2 uptake. GeoChip analysis revealed that decreased CH4 production potential, rather than increased CH4 oxidation potential, may lead to the reduction in net CH4 emissions, and decreased nitrification potential and increased denitrification potential affected N2 O fluxes under WTL conditions. Our study highlights the importance of microbial mechanisms in regulating ecosystem-scale GHG responses to environmental changes.

Grain growth behaviors of Ag-Cu-Zn alloys with different contents of Zn were studied at various heat treatment temperatures and for different holding time. The experimental results show that the grain grows along with the increase of the holding time. The higher the content of Zn is, the larger the grain size will be under the same holding time. The grain growth exponent n increases and the grain growth active energy Q decreases with the increase of the content of Zn

In the Internet age, because of the network security against the background of technical personnel to the existence of the invasion of the network, and can make use of computing tools, make procedural means of invasion, the network intrusion detection is very difficult to analyze and judge. Aiming at this problem, in this paper, on the basis of the use of computing devices, using analysis method of neural network is used to analyze the structure of artificial intelligence, the hidden markov model under the condition of abnormal behavior. Experimental results show that this method is multiple intrusion methods can rapidly accordingly, and has high detection rate, lower false alarm rate.

A new Nylon 11 (PA11)/polyethylene-octene (POE) blends compatibilized by maleic anhydride grafted mixture polyethyleneocten (POE-g-MAH) was prepared through melt blending method. The isothermal crystallization kinetics and melting behaviors of PA11/POE blends were investigated in detail by differential scanning calorimetry (DSC) and polarized optical microscope. The n values of PA11 blending with POE or POE-g-MAH are almost similar with pure PA11, which indicates that the effect of POE and POE-g- MAH on nucleation and growth of PA11 crystal is slight. The overall crystallization rate of PA11/POE blends are higher than ones of pure PA11 at the same crystallization temperatures, but they decrease significantly when POE-g-MAH is added into PA11/POE blends. DSC heating curves of both PA11 and its blends exhibit two melting peaks, but the two melting peak become weaker when POE-g-MAH is add into PA11/POE blend systems. And the spherulite size is reduced signifi cantly by the addition of POE-g-MAH compared with pure PA11 and PA11/POE blends.

In a thermal simulation experiment of gold tubes of closed-system, calculating with the KINETICS and GOR-ISOTOPE KINETICS software, kinetic parameters of gas generation and methane carbon isotopic fractionation from Triassic—Jurassic hydrocarbon source rocks in the Kuqa depression of Tarim Basin are obtained. The activation energies of methane generated from Jurassic coal, Jurassic mudstone and Triassic mudstone in the Kuqa Depression are 197–268 kJ/mol, 180–260 kJ/mol and 214–289 kJ/mol, respectively, and their frequency factors are 5.265times1013s−1, 9.761times1011s−1 and 2.270times1014s−1. This reflects their differences of hydrocarbon generation behaviors. The kinetic parameters of methane carbon isotopic fractionation are also different in Jurassic coal, Jurassic mudstone and Triassic mudstone, whose average activation energies are 228 kJ/mol, 205 kJ/mol and 231 kJ/mol, respectively. Combined with the geological background, the origin of natural gas in the Yinan-2 gas pool is discussed, and an accumulation model of natural gas is thus established. The Yinan-2 gas is primarily derived from Jurassic coal-bearing source rocks in the Yangxia Sag. Main gas accumulation time is 5–0 Ma and the corresponding Ro is in the range from 1.25%–1.95%. The loss rate of natural gas is 25%–30%.

Unraveling the drivers of community structure and succession in response to environmental change is a central goal in ecology. Although the mechanisms shaping community structure have been intensively examined, those controlling ecological succession remain elusive. To understand the relative importance of stochastic and deterministic processes in mediating microbial community succession, a unique framework composed of four different cases was developed for fluidic and nonfluidic ecosystems. The framework was then tested for one fluidic ecosystem: a groundwater system perturbed by adding emulsified vegetable oil (EVO) for uranium immobilization. Our results revealed that groundwater microbial community diverged substantially away from the initial community after EVO amendment and eventually converged to a new community state, which was closely clustered with its initial state. However, their composition and structure were significantly different from each other. Null model analysis indicated that both deterministic and stochastic processes played important roles in controlling the assembly and succession of the groundwater microbial community, but their relative importance was time dependent. Additionally, consistent with the proposed conceptual framework but contradictory to conventional wisdom, the community succession responding to EVO amendment was primarily controlled by stochastic rather than deterministic processes. During the middle phase of the succession, the roles of stochastic processes in controlling community composition increased substantially, ranging from 81.3% to 92.0%. Finally, there are limited successional studies available to support different cases in the conceptual framework, but further well-replicated explicit time-series experiments are needed to understand the relative importance of deterministic and stochastic processes in controlling community succession.

With the rapid development of the network, network security has become one of the most important issues, as it directly affects the interests of the state, enterprises and individuals. Further more, with the increasingly mature of the attack knowledge, complex and diverse attack tools and techniques, the current simple firewall technology has been unable to meet the needs of the people. Facing so many challenges and threats, intrusion detection and prevention technology is bound to become one of the core technologies in the security audit. The iintrusion detection, playing a role of active defense, is an effective complement to the firewall, and is an important part of network security. This paper mainly analyzes the decision tree algorithm and improved Naive Bayes algorithm, proving the effectiveness of the improved Naive Bayes algorithm.

Medical image registration is the key technology to the modern medical images and it is the basic issue of medical image fusion. A medical image registration method integrating features and multiscale information is proposed in the paper. Firstly, the edge feature images obtained by Canny operator are registered by Principal Axes method. Secondly, Harris corner detection method was used to extract the corners of the couple images. Then the corners of the couple images are registered by Iterative Closest Point Algorithm (ICP). Finally, the couple medical images were decomposed by wavelet transform, the mutual information is selected as similar measure, and only the low-frequency sub-images were selected as registration objects. Then, the registration process is begun from the coarse scale until the finest scale by Powell algorithm. Thus the medical images registration can be achieved through the above registration procedure. Experiment results show that this method not only can achieve a higher registration accuracy, but also can reduce the computational time greatly. The accurate registration results also can be achieved in the noisy environment.

Most of the foot deformities relate to the arch collapse or instability, especially the longitudinal one. Though the function of the plantar fascia to the arch height has been investigated by some authors, the other plantar ligaments effect is still unclear. The purpose of this study was to explore the role of the plantar soft tissue in the foot arch biomechanics, including the plantar fascia, spring ligament complex, short plantar ligament and long plantar ligament through normal adult fresh frozen specimens in different injured condition. Also, a three-dimensional finite element model of a normal left foot was developed which was comprising most joints of the foot and consisted of bone segments, major ligaments and plantar soft tissue. These intrinsic ligaments of the foot arch were sectioned in different sequence in the cadaveric experiment, which simulated the different pathologic situation of the plantar ligaments injury to describe the bone segments displacement and stress distribution. The validity of the three-dimensional finite element model was verified by comparing results with experimentally measured data via the displacement and Von-mise stress of each bone segments. The flat foot model both in cadaveric foot and finite element foot was constructed and analyzed.

It has been well studied that foot-ankle biomechanics plays an important role in body locomotion but still be far from well understanding, to some extent for lack of various biomechanical response information under physiological conditions. In this paper, seven unembalmed cadaver feet were loaded under controlled conditions simulating body weight, and biomechanical responses in multi-fields, such as displacement, strain and plantar pressure, were measured with material test machine, digital speckle correlation method (DSCM) measurement system, resistance strain gauge and F-Scan plantar pressure analysis system. Data gained from such multifields experimental measurement were precise and results were interpreted well. This research is aimed at fostering foot-ankle biomechanics well understanding and promoting further research with reasonable and comprehensive analysis.

Plantar fascia release has long been a mainstay in the surgical treatment of persistent heel pain, although its effects on the biomechanics of the foot are not well understood. The purpose of this study was to explore the role of the plantar fascia in the foot arch biomechanics, especially the fore foot motion after plantar fasciotomy via a three-dimensional finite element model of a normal left foot which comprising most joints of the foot. The validity of the three-dimensional finite element model was verified by cadaveric experiment. The vertical and horizontal displacement of the foot bones were calculated as well as the angulation under different situations. The height of the longitudinal arch decreased from 17.923 mm to 19.353 mm after the plantar fasciotomy in sagittal plane. The average contribution of the plantar fascia to the rotation of the foot bones were 34.53%, 22.46% and 12.63% in sagittal, transversal and coronal plane respectively. The plantar fascia is one of the major stabilizing structures of the longitudinal arch of human foot.