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Remote enhancers are thought to interact with their target promoters via physical proximity, yet the importance of this proximity for enhancer function remains unclear. Although some enhancer–promoter loops are cell-type-specific, others are stable across tissues or even display reduced physical proximity upon activation. A major challenge is that relatively few enhancers are functionally characterizedin vivo, making it difficult to draw generalized conclusions about enhancer–promoter looping during developmental gene activation. Here, we investigate the 3D conformation of enhancers during mammalian development by generating high-resolution tissue-resolved contact maps for nearly a thousand mammalian enhancers with knownin vivoactivities in ten murine embryonic tissues. We performed enhancer knockouts in mice, which validated newly identified enhancer–promoter chromatin interactions. The majority of enhancers display tissue-specific 3D conformations, and both enhancer–promoter and enhancer–enhancer interactions are significantly stronger upon enhancer activationin vivo. Less than 14% of enhancer–promoter interactions form stably across tissues; however, corresponding enhancers still display highly-tissue-specific activities indicating that their activity is uncoupled from a chromatin interaction with promoters. We find that these invariant interactions form in the absence of the enhancer and are mediated by adjacent CTCF binding. We also identified putativein vivotarget genes for enhancers linked to congenital malformations, neurodevelopmental disorders, and autism, demonstrating the utility of our dataset for understanding human congenital disorders. Our results highlight the general significance of enhancer–promoter physical proximity for developmental gene activation in mammals.

Inspired by the intricate extracellular matrix (ECM) of natural cartilage and subchondral bone, a heterogenous bilayer hydrogel scaffold is fabricated. Gelatin methacrylate (GelMA) and acryloyl glucosamine (AGA) serve as the main components in the upper layer, mimicking the chondral ECM. Meanwhile, vinylphosphonic acid (VPA) as a non-collagen protein analogue is incorporated into the bottom layer to induce the in situ biomineralization of calcium phosphate. The two heterogenous layers are effectively sutured together by the inter-diffusion between the upper and bottom layer hydrogels, together with chelation between the calcium ions and alginate added to separate layers. The interfacial bonding between the two different layers was thoroughly investigated via rheological measurements. The incorporation of AGA promotes chondrocytes to produce collagen type II and glycosaminoglycans and upregulates the expression of chondrogenesis-related genes. In addition, the minerals induced by VPA facilitate the osteogenesis of bone marrow mesenchymal stem cells (BMSCs). In vivo evaluation confirms the biocompatibility of the scaffold with minor inflammation and confirms the best repair ability of the bilayer hydrogel. This cell-free, cost-effective and efficient hydrogel shows great potential for osteochondral repair and inspires the design of other tissue-engineering scaffolds.

Fantastic structures in nature have inspired much incredible research. Wood, a typical model of anisotropy and hierarchy, has been widely investigated for its mechanical properties and water extraction abilities, although applications in biological areas remain challenging. Delignified wood composite with in situ deposited hydroxyapatite (HAp) and infiltrated polycaprolactone (PCL) is hereby fabricated in an attempt to mimic natural bone. The inherent structure and properties of wood are carefully preserved during the fabrication, showing anisotropic mechanical properties in the radial direction (420 MPa) and longitudinal direction (20 MPa). In addition, it also performs directional liquid transport, effectively inducing the migration and alignment of cells to simulate the uniform seeding behavior of various cells in natural bone. Moreover, the synergistic effect of blended HAp and PCL largely promotes cell proliferation and osteogenic differentiation, providing a promising candidate for bone regeneration materials.

There is a growing interest in developing experimental methods for tracking the developmental cell lineages of a complex organism. The recently developed CRISPR/Cas9-based barcoding method is, although highly promising, difficult to scale up because it relies on exogenous barcoding sequences that are engineered into the genome. In this study, we characterized 78 high-quality endogenous sites in the zebrafish genome that can be used as CRISPR/Cas9-based barcoding sites. The 78 sites are all highly expressed in most of the cell types according to single-cell RNA sequencing (scRNA-seq) data. Hence, the barcoding information of the 78 endogenous sites is recovered by the available scRNA-seq platforms, enabling simultaneous characterization of cell type and cell lineage information.

Severe rill erosion on dump slopes poses a great threat to the ecological environment in mining areas. Vegetation restoration is an effective measure for controlling soil erosion on dump slopes. However, few studies have identified the long-term influence of vegetation restoration on rill development on dump slopes. Therefore, we investigated the rill development characteristics of dump slopes with three typical restoration models (CK: natural restoration; ED: Elymus dahuricus; and AO: Artemisia ordosica) and three recovery time (1 y, 3 y and 5 y). The results showed that vegetation adequately controlled rill erosion on dump slopes. ED and AO could effectively control the development of rills with widths15 cm and depths of 10-20 cm. ED vegetation restoration inhibited the development rill morphology and network better than AO. The rill erosion modulus of the ED slope and AO slope decreased by 76.29%-90.77% and 46.66%-61.49%, respectively, compared with that of natural restoration slopes with recovery time of 1 y, 3 y, and 5 y. ED controlled rill erosion better than AO, but this effect gradually weakened with recovery time. Vegetation coverage contributed 34.99% of the total variation in rill morphology and was the main factor affecting the development of rills on dump slopes. Furthermore, vegetation coverage had a more important role in controlling rill development than did the root system on dump slopes. This study provides valuable information for optimizing vegetation construction for soil loss control on dump slopes.

Topographical factor is one of the most important factors in understanding the formation mechanism of shallow mass movements on gully slopes on the Loess Plateau, China. However, the sensitivity of shallow mass movements on gully slopes to topography is poorly understood. Here, a series of rainfall simulation experiments was performed to quantitatively explore the influences of slope height (1.0 and 1.5 m) and gradient (60° and 70°) on shallow mass movements on the natural loess slopes on the Loess Plateau. Our research observed shallow mass movement processes on undisturbed slopes by using a Topography Meter and collected data that well reflected the nature of the processes. The conducted study has advantageous over traditional methods that are usually used in laboratory tests of backfilled soil. Results showed that the amount of shallow mass movement increased with increased slope height and gradient. The shallow mass movement rates (i.e., gravity erosion rates) increased by approximately 3–8 times with increased slope height from 1.0 m to 1.5 m, and increased by 148%–525% with increased slope gradient from 60° to 70°. The sensitivity coefficient of slope gradients for shallow mass movements was 2.1 times larger than that of slope heights for the shallow mass movements. Slope heights had the greatest effect on earthflow relative to slide and avalanche, whereas slope gradients had the greatest effect on slide. Our results provided insights into natural hazard susceptibility assessment and control erosion processes.

Rainfall can cause serious soil loss in the Loess Plateau hilly and gully region, but little focus has been placed on the extreme rainstorm effects on unpaved loess road soil erosion. A field survey method was used to investigate the erosional effects of the “7.26” heavy rainfall event on unpaved loess roads in the Jiuyuangou watershed of the Loess Plateau, China. The results showed that the average and maximum widths of the eroded gullies that formed on the unpaved roads were 0.65–1.48 m and 1.00–3.60 m, respectively. The average and maximum depths of the eroded gullies were 0.42–1.13 m and 0.75–4.30 m, respectively. The average width-to-depth ratio was 1.31, indicating that the widening effect was greater than the downcutting effect in the eroded gullies. In addition, the gully density ranged from 0.07 to 0.29 m m−2, and the road surface dissection degree ranged from 0.03 to 0.41 km2 km−2. Eroded gullies generally developed at the slope toe of the cut bank side. The average eroded gully width and depth at turns in the road were 1.47–2.64 times and 1.30–3.47 times greater, respectively, than those in other road sections. The road erosion modulus increased from the upper section to the lower section of the roads. The average road erosion modulus of the study catchment was 235,000 t km−2. Turns in the road were associated with collapses, sinkholes and other gravitational erosion phenomena. The amount of road erosion under extreme rainfall conditions is mainly related to the interactions among road length, width, slope and soil bulk density. Our results provide a useful reference for developing further measures for preventing road erosion on the Loess Plateau.

The temporal-spatial changes in flow hydraulics and energy consumption and their associated soil erosion remain unclear during gully headcut retreat. A simulated scouring experiment was conducted on five headcut plots consisting of upstream area (UA), gully headwall (GH) and gully bed (GB) to elucidate the temporal-spatial changes in flow hydraulic, energy consumption, and soil loss during headcut erosion. The flow velocity at the brink of headcut increased as a power function of time, whereas the jet velocity entry to plunge pool and jet shear stress logarithmically or linearly decreased over time. The jet properties significantly affected by upstream flow discharge. The Reynold number, runoff shear stress, and stream power of UA and GB increased as logarithmic or power functions of time, but the Froude number decreased logarithmically over time. The flow of UA and GB was supercritical and subcritical, respectively, and transformed to turbulent with inflow discharge increased. The Reynold number, shear stress and stream power decreased by 56.0 %, 63.8 % and 55.9 %, respectively, but the Froude number increased by 7.9 % when flow dropped from UA to GB. The accumulated runoff energy consumption of UA, GH and GB positions linearly increased with time, and their proportions of energy consumption are 18.3 %, 77.7 % and 4.0 %, respectively. The soil loss rate of the UA-GH-GB system initially rose and then gradually declined and levelled off. The soil loss of UA and GH decreased logarithmically over time, whereas the GB was mainly characterized by sediment deposition. The proportion of soil loss at UA and GH are 11.5 % and 88.5 %, respectively, of which the proportion of deposited sediment on GB reached 3.8 %. The change in soil loss of UA, GH and GB was significantly affected by flow hydraulic and jet properties. The critical energy consumption initiating soil erosion of UA, GH, and GB are 1.62 J s−1, 5.79 J s−1 and 1.64 J s−1, respectively. These results are helpful to reveal the mechanism of gully headcut erosion and built headcut migration model.

It has been challenging to characterize the lineage relationships among cells in vertebrates, which comprise a great number of cells. Fortunately, recent progress has been made by combining the CRISPR barcoding system with single-cell sequencing technologies to provide an unprecedented opportunity to track lineage at single-cell resolution. However, due to errors and/or dropouts introduced by amplification and sequencing, reconstruction of accurate lineage relationships in complex organisms remains a challenge. Thus, improvements in both experimental design and computational analysis are necessary for lineage inference. In this study, we employed single-cell Lineage tracing On Endogenous Scarring Sites (scLOESS), a lineage recording strategy based on the CRISPR-Cas9 system, to trace cell fate commitments for zebrafish larvae. With rigorous quality control, we demonstrated that lineage commitments of complex organisms could be inferred from a limited number of barcoding sites. Together with cell-type characterization, our method could homogenously recover lineage information. In combination with the cell-type and lineage information, we depicted the development histories for germ layers as well as cell types. Furthermore, when combined with trajectory analysis, our methods could capture and resolve the ongoing lineage commitment events to gain further biological insights into later development and differentiation in complex organisms.

Headcut erosion is usually associated with the consumption and transformation of flow energy that occurs when runoff is used to transport sediment. Therefore, flow energy variations in the headcut erosion process are critical in the loess gully region of the Loess Plateau. The aim of this study was to clarify the effects of the flow discharge and slope gradient on flow energy and the response of the headcut erosion process in the gully region of the Loess Plateau. This study examined the headcut erosion process using slope gradients ranging from 1° to 7° in the upstream catchment area and downstream gully bed and inflow discharges ranging from 3.6 to 7.2 m3·h-1. The results showed that the slope gradient has a significant impact on the potential energy in the upstream catchment area; thus, changes in the slope gradients produced changes in the sediment yield. Moreover, the flow discharge significantly influenced not only the potential energy but also the kinetic energy in the upstream catchment area and downstream gully bed. The kinetic energy at the downstream gully bed was 0.03~0.16 J·s-1 lower than that in the upstream catchment area due to the flow drop at the gully head. Greater energy consumption occurred at the gully head than in the upstream catchment area and downstream gully bed, and the gully head contribution to the flow energy consumption was 44.30~64.29%, which increased with increasing flow discharge and decreasing slope gradient. The influence of the slope gradient on the sediment yield was more significant than that of the flow discharge, and a nonlinear regression equation was developed to estimate sediment the yield. The flow energy consumption was significantly correlated with the sediment yield. These findings could improve our understanding of the flow energy characteristics and headcut evolution process during headcut erosion.

The domination of cariogenic bacteria in dental plaque biofilms is the primary cause of dental caries. In view of this, for the purpose of an effective treatment of dental caries, it is of great importance to inhibit the activity of acidogenic bacteria and promote the remineralization of damaged teeth simultaneously. However, the expensive antibacterial agents and poor mineralization ability of materials limit the practical applications. Biomineralization regulated by non-collagenous proteins (NCPs) gives hints to combine the remineralization ability of NCPs with accessible antibacterial property effectively. In this work, we propose a programmed antibacterial and remineralization strategy for the therapy of dental caries based on zinc-substituted hydroxyapatite/ alendronate-grafted polyacrylic acid hybrid nanoneedles (ZHA@ALN-PAA). This hybrid material dissolves in the acidic caries environment and regulate the pH to nearly neutral (6.5). Abundant calcium/ phosphate ions are supplemented and the ALN-PAA embedded in it has also been released, which assists the biomineralization on tooth defect. It has been revealed that the inhibition ratio of ZHA@ALN-PAA against Streptococcus mutans is the highest (11.25 folds that of HA), which originates from the highest zinc ions released (132.9 mg/L). Besides, the interspace of etched enamel is fully filled with regenerated nanorods and the surface microhardness (SMH) is significantly improved (3.68 folds that of etched enamel) after only 3 days of mineralization in vitro. This strategy developed here is simple and cost-effective, which can be referred to design the effective anti-caries materials applied for clinic treatment and daily oral care.

Fisher’s fundamental theorem of natural selection predicts no additive variance of fitness in a natural population. Consistently, studies in a variety of wild populations show virtually no narrow-sense heritability (h2) for traits important to fitness. However, counterexamples are occasionally reported, calling for a deeper understanding on the evolution of additive variance. In this study, we propose adaptive divergence followed by population admixture as a source of the additive genetic variance of evolutionarily important traits. We experimentally tested the hypothesis by examining a panel of ∼1,000 yeast segregants produced by a hybrid of two yeast strains that experienced adaptive divergence. We measured >400 yeast cell morphological traits and found a strong positive correlation between h2 and evolutionary importance. Because adaptive divergence followed by population admixture could happen constantly, particularly in species with wide geographic distribution and strong migratory capacity (e.g., humans), the finding reconciles the observation of abundant additive variances in evolutionarily important traits with Fisher’s fundamental theorem of natural selection. Importantly, the revealed role of positive selection in promoting rather than depleting additive variance suggests a simple explanation for why additive genetic variance can be dominant in a population despite the ubiquitous between-gene epistasis observed in functional assays.

Previous studies have proved that root distribution along gully headwalls greatly alters soil properties and further affects the soil erodibility of gully heads. However, it is not clear whether the gully headcut migration is affected by root distribution and soil properties. Five representative gullies developed in different land uses were selected to clarify the variations of root distribution and soil properties and their effects on headcut migration in the rainy season (May to October 2021) in the Mollisols region of northeast China. Results showed that the 68.4%–93.3% of root mass density and 65.6–88.5% of root length density were concentrated in 0–30 cm soil layer of gully heads, and the roots of 85%. The gullies developed in farmlands had relatively higher soil compactness, shear strength and aggregate stability, but lower organic matter (OMC), disintegration capacity and soil permeability than those developed in woodlands, unpaved roads in farmland and stable gully-beds. Changes in soil properties of gully heads were closely related to root density. The linear, areal, and volumetric migration rate of gully heads varied greatly and were 1.07–35.11 m yr−1, 28.95–562.46 m2 yr−1 and 56.82–6626.37 m3 yr−1, respectively, with the average of 9.07 m yr−1, 156.92 m2 yr−1 and 1503.02 m3 yr−1, respectively. The change in headcut migration rate was significantly affected by root density, soil properties and drainage area, of which soil texture, OMC, soil aggregate structure, and the drainage area were the critical factors influencing headcut migration in the Mollisols region of northeast China.

Gully headcut erosion is recognized as the primary process of gully erosion and is the main contributor to sediment yield of gully erosion. However, the proportion of jet flow and on-wall flow induced by headcut and its effects on soil loss and plunge pool morphology are still unclear. A simulated flow-scouring experiment was conducted to explore the proportion of jet flow and on-wall flow and their contributions to soil loss and the effect of on-wall flow erosion on plunge pool morphology under different flow discharge (q0 = 3.0–7.2 m3 h−1) and headwall height (H0 = 0.3–1.2 m) conditions. Our results showed that jet flow and on-wall flow accounted 15.7% − 22.6% and 77.4% − 84.3% of total flow volume upstream headcut, respectively. Jet flow, on-wall flow and their interaction contributed 53.5%, 34.9% and 11.6% of total soil loss amount, respectively. Furthermore, H0 exhibited greater effect on soil loss caused by jet flow and its interaction with on-wall flow, but the soil loss caused by on-wall was mainly controlled by q0. The width and depth of plunge pool logarithmically increased with scouring time, and the q0 and H0 significantly affected the development of plunge pool morphology. On-wall flow reduced plunge pool depth by 27.8%–71.4%, and it weakened plunge pool width by 24.3%−57.3% only under H0 of 0.3–0.9 m, but for H0 of 1.2 m and q0 of >4.8 m3 h−1, it improved the plunge pool width by 7.5%. The energy consumption of jet flow showed the closest relationship with plunge pool morphology. The concentrated flow upstream gully head exhibited the stronger effect on plunge pool morphology than H0. This study is helpful to deepen the understanding of gully erosion mechanism and provide scientific reference for the design of gully erosion prevention and control measures.

Electrical stimulation (ES) exhibits a positive role in promoting the cell activity of osteoblasts. Conducting polymers have the advantages of biocompatibility, good environmental stability and easy synthesis, which have been widely used as charge carriers for electrical stimulation; moreover, considering clinical applications, biomaterial-related infection is an important issue that needs to be solved. Thus, conducting polymers with both antibacterial and osteogenic properties are highly demanded for effect repair. However, it remains a challenge to combine these two characteristics efficiently in a simple way. Herein, an Ag-loaded poly(amide-amine) dendrimer was prepared by a simple chemical reduction procedure, which acted as a dopant for the polymerization of polyaniline (PANI) on biomedical titanium (Ti) sheets. The obtained PANI coating showed outstanding antibacterial properties against Gram-negative (E. coli) and Gram-positive (S. aureus) microbes with a 1000-fold increase when compared with that of pure Ti. In addition, note that the polymer coating together with ES facilitated the proliferation and differentiation of MC3T3. The alkaline phosphatase (ALP) activity and intracellular calcium content of the cells showed a 19.09% and 24.02% increase, respectively, when compared with the case of electrically stimulated Ti after 12 days. Moreover, the existence of PAMAM facilitated mineralization. The strategy developed herein is simple and can be easily manipulated, which shows potential applications in the coating of implants for hard tissue repair.

As the hardest tissue in human body, enamel has attracted significant research interest in recent years. It has been acknowledged that the highly oriented arrangement of hydroxyapatite (HAp) crystallites of the enamel plays a crucial role owing to its excellent mechanical properties. So far, the preparation of enamel-like HAp crystallites on general substrates using mild conditions remains a challenge. Here, inspired by natural enamel, we developed a biomimetic, anodic alumina oxide (AAO)-assisted, double-layered gel system to fabricate well-oriented HAp crystals on universal surfaces. The one-directional ion flow was elaborately modulated for mineralization based on the synergistic effect of the double-layered gel and the AAO membrane, leading to highly oriented HAp crystallites. In addition, the introduction of polydopamine as a nucleating agent makes this method applicable for a wide range of substrates. The as-prepared minerals show a well-aligned enamel-like structure, exhibiting an elastic modulus of 52 GPa and nanohardness of 0.73 GPa, which are close to those of natural enamel. We envision that the strategy has potential applications for tooth repair and will provide guidelines for the mineralization of other inorganic minerals.

Soil erodibility is an indispensable parameter for predicting soil erosion and evaluating the benefits of soil and water conservation. Slope situation can alter revegetation and its effects on soil properties and root traits, and thus may affect soil erodibility. However, whether slope situation will change the effect of revegetation on soil erodibility through improving soil properties and root traits has rarely been evaluated. Therefore, this study was conducted to detect the response of soil erodibility to slope situations (loess-tableland, hill-slope and gully-slope) in a typical watershed of the Loess Plateau. Five soil erodibility parameters (saturated soil hydraulic conductivity, SHC; mean weight diameter of aggregates, MWD; clay ratio, CR; soil disintegration rate, SDR; soil erodibility factor, K) and a comprehensive soil erodibility index (CSEI) are selected to clarify the study targets. The results revealed that soil properties, root traits, soil erodibility parameters and CSEI were affected by slope situation significantly. Soil and root can explain 79.7%, 79.1% and 69.8% of total variance in soil erodibility of loess-tableland, hill-slope and gully-slope, respectively. Slope situation influenced soil erodibility by changing the effects of revegetation on soil properties and root traits. Evidently, the slope situation greatly changed the relations between CSEI and soil and root parameters, whereafter a model considering slope situation (slope steepness), sand, organic matter content and root surface area density was reliable to estimate soil erodibility (CSEI). Our study suggested that the Armeniaca sibirica, the combination of Bothriochloa ischcemum and Robinia pseudoacacia and the combination of Armeniaca sibirica and Lespedeza bicolor can be used as the optimal selection for mitigating soil erodibility of loess-tableland, hill-slope and gully-slope, respectively. This study is of great significance in optimizing the spatial layout of soil and water conservation measures for different slope situations of the Loess Plateau.

Direct administration of salmon calcitonin (sCT) by subcutaneous or intramuscular injection is limited by its low efficiency. Drug delivery systems with sustained delivery properties and high bioactivity are urgently needed. For clinical applications an economical and effective carrier is required, which has been a challenge until now. In this study, a simple alginate/alginate sulfate-sCT (Alg/AlgS-sCT) complex was successfully constructed for sustained release of sCT. The negatively charged sulfate groups facilitate bonding with sCT, which avoids the burst release of sCT and extends the release time up to 15 d (it is only 2 d for pure sCT). More importantly, the bioactivity of the released sCT is not affected during such a long release time, suggesting a conformation similar to that of native sCT. In vitro analysis implies that the complex is biocompatible. Moreover, the combination of AlgS and sCT synergistically improves the osteogenic ability of MC3T3 cells, which show higher alkaline phosphatase levels and intracellular and extracellular calcium ion concentrations. The concentration of intracellular calcium ions is 5.26-fold higher than in the control group after 10 d of incubation. This simple yet effective system has potential applications in clinical trials and may inspire the design of other protein delivery systems.

Bloodstream infections rank among the most serious causes of morbidity and mortality in hospitalized patients, partly due to the long period (up to one week) required for clinical diagnosis. In this work, we have developed a sensitive method to quickly and accurately identify bacteria in human blood samples by combining optimized matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS) and efficient immunoaffinity enrichment/separation. A library of bacteria reference mass spectra at different cell numbers was firstly built. Due to a reduced sample spot size, the reference spectra could be obtained from as few as 10 to 10(2) intact bacterial cells. Bacteria in human blood samples were then extracted using antibodies-modified magnetic beads for MS fingerprinting. By comparing the sample spectra with the reference spectra based on a cosine correlation, bacteria with concentrations as low as 500 cells per mL in blood serum and 8000 cells per mL in whole blood were identified. The proposed method was further applied to positive clinical blood cultures (BCs) provided by a local hospital, where Escherichia coli and Staphylococcus aureus were identified. Because of the method's high sensitivity, the BC time required for diagnosis can be greatly reduced. As a proof of concept, whole blood spiked with a low initial concentration (10(2) or 10(3) cells per mL) of bacteria was cultured in commercial BC bottles and analysed by the developed method after different BC times. Bacteria were successfully identified after 4 hours of BC. Therefore, an entire diagnostic process could be accurately accomplished within half a day using the newly developed method, which could facilitate the timely determination of appropriate anti-bacterial therapy and decrease the risk of mortality from bloodstream infections.

Articular cartilage, due to its avascular nature and the low cell density, is hard to regenerate once damaged, thus requiring surgical intervention. Natural cartilage exhibits a complex anisotropic feature with nonlinear and viscoelastic mechanical properties owning to complicated architecture making it attractive to mimic the structure. Here, we demonstrate a three-zone composite hydrogel with superficial, middle and deep zones incorporating into cellulose fabric, cellulose nanofiber and wood cellulose fiber respectively to prepare a stack layout composite hydrogel inspired by cartilage architecture with zone-dependent mechanical properties. The results indicate that the three-zone cellulose reinforced polyethylene glycol-based composite hydrogel demonstrates hydrogel creates native-like articular cartilage with zone-dependent, nonlinear and viscoelastic mechanical properties. The compressive moduli of the superficial, middle and deep zones are 298 kPa, 182 kPa and 9.8 MPa respectively, and the middle zone possess obvious nonlinear features. Furthermore, the highly aligned wood frame channels endow deep zone with nutrition and cell transport behaviors which are beneficial to the process of cartilage regeneration. Therefore, the bio-inspired three-zone composite hydrogel has a promising potential application for cartilage repair.

The effects of vegetation restoration on soil erosion resistance of gully head, along a revegetation age gradient, remain poorly understood. Hence, we collected undisturbed soil samples from a slope farmland and four grasslands with different revegetation ages (3, 10, 18, 25 years) along gully heads. Then, these samples were used to obtain soil detachment rate of gully heads by the hydraulic flume experiment under five unit width flow discharges (2&ndash, 6 m3 h). The results revealed that soil properties were significantly ameliorated and root density obviously increased in response to restoration age. Compared with farmland, soil detachment rate of revegetated gully heads decreased 35.5% to 66.5%, and the sensitivity of soil erosion of the gully heads to concentrated flow decreased with revegetation age. The soil detachment rate of gully heads was significantly related to the soil bulk density, soil disintegration rate, capillary porosity, saturated soil hydraulic conductivity, organic matter content and water stable aggregate. The roots of 0&ndash, 0.5 and 0.5&ndash, 1.0 mm had the highest benefit in reducing soil loss of gully head. After revegetation, soil erodibility of gully heads decreased 31.0% to 78.6%, and critical shear stress was improved by 1.2 to 4.0 times. The soil erodibility and critical shear stress would reach a stable state after an 18-years revegetation age. These results allow us to better evaluate soil vulnerability of gully heads to concentrated flow erosion and the efficiency of revegetation.

Vegetation is widely used for controlling landslides around the world; however, rainfall-induced shallow landslides occur frequently on vegetation-covered slopes on the Chinese Loess Plateau during the rainy season. To probe this phenomenon, we conducted on-site investigations and measurements in the Nanxiaohegou catchment on the Loess Plateau to explore the effects of soil properties and vegetation on shallow loess landslides. Most of the loess landslides on vegetation-covered slopes were small scale with depths ranging from 0.3 m to 1.0 m, corresponding to the topsoil being saturated due to rainfall. Majority of shallow landslides occurred on herbage-covered area, which made up 69% of total landslides. There are significant differences in soil properties between the upper layer (root-soil composite) and the lower layer (loess) of the sliding surface. Our study demonstrated that root plays a leading role in landslide erosion and that the most adverse effect of vegetation on landslides is mainly the increase in soil moisture content in the shallow soil through the root zone creating preferential infiltration flow paths. There are remarkable differences in landslide erosion depths and landslide erosion intensities among different vegetation types. The landslide erosion depth and landslide erosion intensity increased linearly with increasing main root depth, indicating that the vegetation root depth determines the landslide erosion intensity during rainfall. Therefore, the potential implications of vegetation especially the herbage to promote landslide occurrences during rainfall should be given more attention in the future.

Thrombosis remains one of the leading causes of mortality and morbidity in the world. Thrombin is a key enzyme involved in the blood clotting processes, which can be intervened by low concentrations of Hirudin. The C-terminal dodecapeptide of Hirudin was capable of inhibiting thrombosis. This peptide has been partially randomized in this report, and the coding sequences have been expressed in yeast as chimerical peptides for secretion into the culture media. Two other semi-random modules have been processed likewise. The supernatant was subsequently tested for anti-thrombin activities. DNA sequencing indicated that the putative positive clone encoded a single serine residue followed by a stop codon. The Ninhydrin assay of the culture supernatant of the positive clone indicated a high content of amino acid. Electrospray Mass Spectrometry showed a distinct peak at 430.5 when the expression products fromPichia pastoriswere examined, suggesting that the compound may be a dimannosylated serine, as yeast possesses glycosylation at serine residues. The observed effects of α-Mannosidase treatments on the function of yeast induction products are consistent with this assumption. Partial randomization of peptides and proteins may accelerate directed evolution, yielding unprecedented number of variants for functional interrogation and drug development.

Enamel, dentin and bone are calcified hard tissues in the human body that play significant roles in food mastication and movement support. Generally, hard tissues lack the ability of self-repair, except for the regeneration ability of bone for small-scale defects. Fabrication of man-made repair materials is therefore highly demanded. In this review, following a bioinspired strategy, we describe the composition and multiscale structures of different hard tissues, and highlight the key points for the reconstruction of hard tissues. Finally, bioinspired tissue repair techniques ranging from molecule-induced mineralization, to microscale assembly to macroscaffold fabrication are summarised.

A continuous cell line, SYSU-OfHe-C, from larval hemocytes of corn borer, Ostrinia furnacalis was established. With increasing passages, the cells grew increasingly faster, and approximately 45% of the cells were in division at passage 55. The culture was mainly composed of two types of cells, granulocytes and plasmatocytes, which showed different division and proliferation behaviors, but possessed similar phagocytic ability. Its spreading ability was significantly weaker than that of hemocytes from naïve larva; however, it could be promoted by larval plasma. Furthermore, its encapsulation ability was also promoted by larval plasma to form multilayer capsules on Sephadex A-25 beads. Finally, the expression of several immune-related genes was verified after provocation by microbes or Sephadex beads. These results indicated that the cell line possessed immune ability depending on the presence of plasma of naïve larvae and are beneficial to studies of insect cellular systems.

Rill erosion is one of the main forms of soil erosion of the hillslopes on the Loess Plateau of China. Few studies have evaluated the effects of land use on the distribution and morphology of rills under extreme rainstorms. A total of 50 rill survey sites were selected in a typical watershed of the Loess Plateau of China to investigate the rill distribution and morphology of three land uses (fallow land, FL; slope farmland, SF; and annual grassland, AG) under extreme rainstorm conditions (called “7·26” rainstorm). Seven parameters (rill width, rill depth, width-depth ratio, cross-section area, rill density, degree of rill dissection and rill erosion modulus) were used to characterize rill morphology, and the basic soil and vegetation properties (bulk density, particle size distribution, and vegetation coverage) and topographic factors (slope length, gradient, direction) were measured. It was found that rills developed on three land uses, and those with widths ranging from 5 to 20 cm accounted for >80%. Rills developed on FL were deeper than those on SF and AG. Almost all rills on FL had a depth of 5–20 cm (90.3%), while the depth of rills on SF and AG were mainly smaller than 15 cm (91.5% and 91.9%, respectively). In addition to width, rill depth and cross-section area of SF and AG were also significantly less than those of FL. SF and FL had a relatively high width-depth ratio and dissection degree. However, land use had no significant effect on rill density. Crop plantations (SF) and grass restoration (AG) significantly reduced rill erosion modulus (28.70% and 45.07% reduction, respectively). Land use, topography, soil, and vegetation factors significantly affected rill morphology (p = 0.001) based on redundancy analysis (RDA) and can explain 48.0% of the total variability of rill morphology, with slope length, vegetation coverage and slope gradient having the greatest influences. Most of the rill morphological parameters significantly decreased as the vegetation coverage increased but they significantly increased with increasing slope length and slope gradient. This study clearly illustrates the severe rill erosion caused by this rainstorm, and indirectly indicates that crop harvesting (FL) aggravates rill erosion and that revegetation (AG) can effectively contain rill erosion. Therefore, rehabilitation efforts should be focused on revegetation (grassland and/or woodland) on steep slopes to control soil erosion.

Bacterial typing is of great importance in clinical diagnosis, environmental monitoring, food safety analysis, and biological research. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is now widely used to analyze bacterial samples. Identification of bacteria at the species level can be realized by matching the mass spectra of samples against a library of mass spectra of known bacteria. Nevertheless, in order to reasonably type bacteria, identification accuracy should be further improved. Herein, we propose a new framework to the identification and assessment for MALDI-MS based bacterial analysis. Our approach combines new measures for spectra similarity and a novel bootstrapping assessment. We tested our approach on a general data set containing the mass spectra of 1741 strains of bacteria and another challenging data set containing 250 strains, including 40 strains in the Bacillus cereus group that were previously claimed to be impossible to resolve by MALDI-MS. With the bootstrapping assessment, we achieved much more reliable predictions at both the genus and species level, and enabled to resolve the Bacillus cereus group. To the best of the authors' knowledge, our method is the first to provide a statistical assessment to MALDI-MS based bacterial typing that could lead to more reliable bacterial typing.