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Vertically neutral collapse of a pulsating bubble occurs when the boundaries above or below the bubble balance the buoyancy effect over a pulsation. In this study, the vertically neutral collapse of a bubble near a vertical rigid wall below the free surface is investigated. The boundary integral method (BIM) is employed to model the bubble dynamics with an open-domain free surface. Moreover, this method is validated against several buoyant bubble experiments. Bubble dynamics in such conditions are associated with three dimensionless parameters: the bubble-free surface distance $\gamma _{{f}}$ , bubble–wall distance $\gamma _{{w}}$ and buoyancy parameter $\delta$ . We derive the Kelvin impulse of a spherical bubble and the algebraic relationship for vertically neutral collapse, which proves to be accurate for predicting vertically neutral collapse when the bubble is relatively far from the boundaries. Four patterns of the vertically neutral collapse of the bubble for different $\gamma _{{w}}$ and $\gamma _{{f}}$ are identified: (i) formally downward jet; (ii) annular collapse; (iii) horizontal jet; and (iv) weak jet. Despite the downward jet shape, the ‘formally downward jet’ is in the vertically neutral collapse state in terms of the profile of toroidal bubbles and the orientation of local high-pressure zones around the bubble at jet impact. A bulge with a high curvature above the bubble in the ‘annular collapse’ pattern is formed during bubble collapse under two local high-pressure zones at the left and right extremities of the bubble. The ‘horizontal jet’ pattern has the greatest potential to attack the wall, and the power laws of the moment of the jet impact, jet velocity and bubble displacement with respect to the theoretical Kelvin impulse are discussed. In particular, we quantitatively illustrate the role of the free surface on bubble migration towards the wall through the variational power-law exponents of the bubble displacement with respect to $\gamma _{{w}}$ .

High-speed water entry is a transient hydrodynamic process that is accompanied by strongly compressible flow, free surface splash, cavity evolution and other nonlinear hydrodynamic phenomena. To address these problems, a novel fluid–structure interaction (FSI) scheme based on the immersed boundary method is proposed which is suitable for strongly compressible multiphase flows. In this scheme, considering the multiphase interfaces at the immersed boundary, an improved immersed boundary method for effectively suppressing the non-physical force oscillation is proposed. Additionally, a quaternion-based six degrees of freedom motion system is used to describe rigid body motion, and the multiphase flow Eulerian finite element method is applied as the fluid solver. Using analytical solutions, experimental data and literature data, the accuracy and robustness of the FSI scheme are validated. Finally, the high-speed water entry of the slender body with different noses is investigated, and the hydrodynamic loads including the axial and normal drag forces and the bending moment are extensively discussed. The hydrodynamic load and motion trajectory are determined by the nose configuration. The tail slamming phenomenon is the primary focus, and it is revealed that its formation is primarily related to the pitch moment formed at the stage of crossing the free surface. Tail slamming also causes violent impact loads, especially bending moments, which may cause slender projectiles to break off. Finally, to combine the features of the flat and hemispherical noses, the water entry of the projectile with a truncated hemispherical nose is simulated and discussed.

In this work, we established a novel theory for the dynamics of oscillating bubbles such as cavitation bubbles, underwater explosion bubbles, and air bubbles. For the first time, we proposed bubble dynamics equations that can simultaneously take into consideration the effects of boundaries, bubble interaction, ambient flow field, gravity, bubble migration, fluid compressibility, viscosity, and surface tension while maintaining a unified and elegant mathematical form. The present theory unifies different classical bubble equations such as the Rayleigh–Plesset equation, the Gilmore equation, and the Keller–Miksis equation. Furthermore, we validated the theory with experimental data of bubbles with a variety in scales, sources, boundaries, and ambient conditions and showed the advantages of our theory over the classical theoretical models, followed by a discussion on the applicability of the present theory based on a comparison to simulation results with different numerical methods. Finally, as a demonstration of the potential of our theory, we modeled the complex multi-cycle bubble interaction with wide ranges of energy and phase differences and gained new physical insight into inter-bubble energy transfer and coupling of bubble-induced pressure waves.

This study evaluated the effects of the dietary starch amylose/amylopectin ratio on growth performance, rumen fermentation and blood parameters, carcass characteristics and marbling score, and meat fatty acid profiles and transcriptional changes in the genes involved in the gluconeogenesis pathway in Chinese Qinchuan cattle. Forty-five cattle were randomly divided into three groups. The bulls were fed a control diet (middle amylose/amylopectin ratio=0.47) or diets with either waxy corn starch (WS) inclusion (low amylose/amylopectin ratio=0.23) or pea starch (PS) inclusion (high amylose/amylopectin ratio=0.60) for 90 days. The bulls were individually allowed to receive the diets at the daily amount of at least 2.1% of their individual BW twice daily. The bulls were weighed at 45-day intervals, and blood and rumen fluid samples were also collected at 45-day intervals. The bulls were slaughtered and longissimus thoracis (LT) samples were collected for meat quality measurements. Compared with PS, the average daily gain (ADG) and feed efficiency in control and WS were increased (P0.05) among the three groups. Compared with PS, the serum insulin concentration in WS was increased (P0.05). Chemical and physio-chemical compositions of LT did not differ (P>0.05) among the three groups. In conclusion, diets with low or middle amylose/amylopectin ratios increased the backfat thickness, and tended to improve ADG, but had no effect on other carcass characteristics, fat content in the LT, or the expression of hepatic genes related to the gluconeogenesis pathway in Chinese Qinchuan cattle.

Atrial fibrillation (AF) is one of the most common arrhythmias, associated with high morbidity, mortality, and healthcare costs, and it places a significant burden on both individuals and society. Anti-arrhythmic drugs are the most commonly used strategy for treating AF. However, drug therapy faces challenges because of its limited efficacy and potential side effects. Catheter ablation is widely used as an alternative treatment for AF. Nevertheless, because the mechanism of AF is not fully understood, the recurrence rate after ablation remains high. In addition, the outcomes of ablation can vary significantly between medical institutions and patients, especially for persistent AF. Therefore, the issue of which ablation strategy is optimal is still far from settled. Computational modeling has the advantages of repeatable operation, low cost, freedom from risk, and complete control, and is a useful tool for not only predicting the results of different ablation strategies on the same model but also finding optimal personalized ablation targets for clinical reference and even guidance. This review summarizes three-dimensional computational modeling simulations of catheter ablation for AF, from the early-stage attempts such as Maze III or circumferential pulmonary vein isolation to the latest advances based on personalized substrate-guided ablation. Finally, we summarize current developments and challenges and provide our perspectives and suggestions for future directions.

The jetting behaviour and migratory characteristics of a laser-induced cavitation bubble in a rectangular channel are investigated both experimentally and numerically, for various combinations of the geometric and physical parameters of the system. High-speed photography is used to visualize the temporal development of the bubble shape, the formation of liquid jets during bubble collapse, and the bubble displacement in contact with the sidewalls of the channel during two oscillation cycles of the bubble. The bubble profiles, pressure contours and velocity vectors ambient to the bubble are obtained through numerical simulation results by using an Eulerian finite element method with a compressible liquid impact model. The jetting behaviour of the bubble varies between single jet formation and the formation of three liquid jets directed towards each wall of the channel. The numerical calculations indicate that the liquid jets directed towards the sidewalls of the channel reach maximum velocities of 100 m s−1 while the peak velocity of the liquid jet directed towards the channel endwall is about 55 m s−1. A small bubble generated close to a sidewall of the channel develops only a single inclined jet during collapse. Such jets can reach velocities of up to 110 m s−1. A bubble displacement in contact with the sidewalls of the channels of 350 μm was observed during the first two oscillation cycles for a bubble with a maximum diameter slightly smaller than the height of the channel. The results of our investigations are compared to previous results obtained in similar configurations.

Numerous methods have been published to segment the infarct tissue in the left ventricle, most of them either need manual work, post-processing, or suffer from poor reproducibility. We proposed an automatic segmentation method for segmenting the infarct tissue in left ventricle with myocardial infarction. Cardiac images of a total of 60 diseased hearts (55 human hearts and 5 porcine hearts) were used in this study. The epicardial and endocardial boundaries of the ventricles in every 2D slice of the cardiac magnetic resonance with late gadolinium enhancement images were manually segmented. The subsequent pipeline of infarct tissue segmentation is fully automatic. The segmentation results with the automatic algorithm proposed in this paper were compared to the consensus ground truth. The median of Dice overlap between our automatic method and the consensus ground truth is 0.79. We also compared the automatic method with the consensus ground truth using different image sources from different centers with different scan parameters and different scan machines. The results showed that the Dice overlap with the public dataset was 0.83, and the overall Dice overlap was 0.79. The results show that our method is robust with respect to different MRI image sources, which were scanned by different centers with different image collection parameters. The segmentation accuracy we obtained is comparable to or better than that of the conventional semi-automatic methods. Our segmentation method may be useful for processing large amount of dataset in clinic.

The Permian–Triassic Mass Extinction (PTME) resulted in the most severe loss of life in the history of the earth, both marine and terrestrial ecosystems suffered heavy losses simultaneously, and the biotic recovery process was difficult for both. There are many studies on the timing and pattern of this mass extinction, however, the consistency of the recovery between the marine and terrestrial facies remains controversial. In particular, few metazoans survived and the deposits were dominated by the microbialites during the Early Triassic. The reappearance of the metazoans signified the beginning of the biotic recovery. In this paper, we measured the trace fossils of the Heshanggou Formation in western Henan, North China, which plays an important role in the transformation from the flourishing of the microorganisms to the recovery of metazoans. We quantitatively described the characteristics and measured the diameter, depth, abundance and diversity of the trace fossils. Based on the acquired data, the lower part of the Heshanggou Formation is confined to simple, small, vertical burrows, suggesting that the ecological environment was suitable for the survival of special species. In the middle part, the vertical burrows become deeper, which may be due to the adaptation of organisms to the harsh environment. Disturbance is more intense and the diversity clearly increases in the upper part. Through the increasing bioturbation and diversity of the trace fossils, we found a gradual biotic recovery pattern in the Early Triassic, and the recovery mode is similar to marine ichnofossils in South China.

We report varied microbially induced sedimentary structures (MISS), and other sedimentary surface textures, from the Induan (Early Triassic) Sunjiagou Formation and Liujiagou Formation in the Xingyang, Dengfeng, Jiyuan and Yiyang areas, western Henan Province, North China. Microanalysis shows that these MISS are characterized by a U-shaped structure, thin clayey laminae, and discontinuous mica sheet that are arranged parallel to the bedding plane, as well as directionally oriented quartz grains floating in lamina, which are indicative of a biogenic origin. The MISS of the studied area were probably affected by four main factors, including the end-Permian mass extinction, the megamonsoon, the adapted sedimentary environment, and the sediment supply, and they possess significant stratigraphic correlation. Abundant microbial-related sedimentary structures from the study area indicate that continental ecosystems were severely devastated in the aftermath of the Permian-Triassic biocrisis. These sedimentary structure assemblages, including MISS, red beds, conglomerate layers, and calcareous concretions in the western Henan Province, show a specific, post-extinction continental ecosystem that was characterized by microflora dominance, monotonous and rare fossils, extreme hot climate, soil ecosystem devastation, and poor vegetation.

In this paper, the dynamic characteristics of the bubble in a broken confined domain are studied. The broken confined domain is composed of a solid wall and a plate that has a hole. The axisymmetric numerical model is established by combining the Eulerian finite-element method with volume of fluid (VOF) method, and is validated by comparing the results with those from an experiment. Then the influences of the wall distance, plate distance and size of the hole are analyzed. The results show that cavity-attraction jet caused by the hole and annular jet caused by the upper solid wall compete with each other to dominate the bubble dynamics. The cavity-attraction jet develops earlier, but slower. Thus, jet load in the bubble stage is mainly generated by the annular jet with a higher impact speed. Within a certain range, the closer the hole is to the bubble or the smaller the hole, the longer the pulsation period of the bubble will be.

The injury mechanism of a pelvic fracture is primarily high-energy injury, and it is easily combined with injuries to other tissues and organs. This study aimed to investigate the clinical effectiveness of early diagnosis and treatment of pelvic fractures and associated injuries in children.The diagnosis and treatment of 60 children with pelvic fractures and associated injuries who were admitted to our hospital from January 2005 to December 2016 were retrospectively analyzed. Among these patients, 36 were male, and 24 were female. The patients' ages ranged within 2-15 years, with an average of 7.6 years old. The pelvic fractures were classified based on the Torode and Zieg classification; among the patients, 12 had type I, 16 had type II, 20 had type III, and 12 had type IV. All patients received early diagnosis, immediate anti-shock measures, aggressive treatment of associated injuries, and early reduction and fixation of the pelvic fractures after admission.Of the 60 patients, 28 had injuries caused by traffic accidents, 26 had injuries caused by falling from high places, and 16 had injuries caused by compressing or crushing. Eight patients had unilateral pubic bone fracture or pubic symphysis separation that involved posterior pelvic fracture or sacroiliac joint separation, and two had fractures that affected the anterior ring or acetabulum. Moreover, 26 patients had hemorrhagic shock, 18 had traumatic brain injury, 14 had fractures at other sites, 8 had pelvic large vessel injuries, 8 had ipsilateral femoral and proximal femoral fractures, 8 had retroperitoneal hematoma, 8 had urinary system injury, 6 had perineal laceration and vaginal trauma, 6 had spinal cord injury, 4 had intestinal injuries, 4 had soft tissue contusions, and 4 had sacral nerve injury. During the follow-up (average: 48 months), six children died. The evaluation results of the curative effect were excellent in 32 children, good in 18, and poor in 4; the 'excellent' and 'good' rate was 92.5% (50/54).Early diagnosis, reduction, and fixation and timely treatment of associated injuries might achieve better clinical efficacy and are worthy of clinical promotion.Associated Injuries, Childhood, Diagnosis, Fracture, Pelvic, Treatment.Il meccanismo di lesione di una frattura pelvica è principalmente una lesione ad alta energia ed è facilmente combinabile con lesioni ad altri tessuti e organi. Questo studio mirava a studiare l’efficacia clinica della diagnosi precoce e del trattamento delle fratture pelviche e delle lesioni associate nei bambini. Sono stati analizzati retrospettivamente la diagnosi e il trattamento di 60 bambini con fratture pelviche e lesioni associate che sono stati ricoverati nel nostro ospedale da gennaio 2005 a dicembre 2016. Tra questi pazienti, 36 erano maschi e 24 erano femmine. L’età dei pazienti era compresa tra 2 e 15 anni, con una media di 7,6 anni. Le fratture pelviche sono state classificate in base alla classificazione Torode e Zieg; tra i pazienti, 12 avevano tipo I, 16 avevano tipo II, 20 avevano tipo III e 12 avevano tipo IV. La diagnosi dopo il ricovero è stata precoce in tutti i pazienti, che sono stati trattati immediatamente per lo stato di shock, e con un trattamento aggressivo delle lesioni associate, e con riduzione e fissazione precoci delle fratture pelviche. Risultati: Dei 60 pazienti, in 28 le lesioni erano derivate da incidenti stradali; in 26 le lesioni erano conseguenti a precipitazioni dall’alto; in 16 le lesioni derivavano da compressione o schiacciamento. Otto pazienti presentavano una frattura unilaterale dell’osso pubico o separazione della sinfisi pubica che comportava una frattura pelvica posteriore o una separazione dell’articolazione sacroiliaca e due presentavano fratture che interessavano l’anello anteriore o l’acetabolo. Inoltre, 26 pazienti presentavano shock emorragico, 18 avevano trauma cranico, 14 avevano fratture in altri siti, 8 avevano lesioni dei grandi vasi pelvici, 8 presentavano fratture ipsilaterali e prossimali del femore, 8 avevano ematoma retroperitoneale, 8 avevano lesioni del sistema urinario, 6 avevano lacerazione perineale e trauma vaginale, 6 avevano lesioni del midollo spinale, 4 avevano lesioni intestinali, 4 avevano contusioni dei tessuti molli e 4 avevano lesioni del nervo sacrale. Durante il follow-up (media: 48 mesi), sono morti sei bambini. I risultati della valutazione dell’effetto curativo sono stati eccellenti in 32 bambini, buoni in 18 e poveri in 4; la percentuale “eccellente” e “buona” era del 92,5% (50/54). In conclusione la diagnosi precoce, riduzione e fissazione e trattamento tempestivo delle lesioni associate potrebbero raggiungere una migliore efficacia clinica e sono altamente consigliabili per la pratica clinica.

Rapid evolutionary radiations are among the most challenging phylogenetic problems, wherein different types of data (e.g., morphology and molecular) or genetic markers (e.g., nuclear and organelle) often yield inconsistent results. The tribe Arundinarieae, that is, the temperate bamboos, is a clade of tetraploid originated 22 Ma and subsequently radiated in East Asia. Previous studies of Arundinarieae have found conflicting relationships and/or low support. Here, we obtain nuclear markers from ddRAD data for 213 Arundinarieae taxa and parallel sampling of chloroplast genomes from genome skimming for 147 taxa. We first assess the feasibility of using ddRAD-seq data for phylogenetic estimates of paleopolyploid and rapidly radiated lineages, optimize clustering thresholds, and analysis workflow for orthology identification. Reference-based ddRAD data assembly approaches perform well and yield strongly supported relationships that are generally concordant with morphology-based taxonomy. We recover five major lineages, two of which are notable (the pachymorph and leptomorph lineages), in that they correspond with distinct rhizome morphologies. By contrast, the phylogeny from chloroplast genomes differed significantly. Based on multiple lines of evidence, the ddRAD tree is favored as the best species tree estimation for temperate bamboos. Using a time-calibrated ddRAD tree, we find that Arundinarieae diversified rapidly around the mid-Miocene corresponding with intensification of the East Asian monsoon and the evolution of key innovations including the leptomorph rhizomes. Our results provide a highly resolved phylogeny of Arundinarieae, shed new light on the radiation and reticulate evolutionary history of this tribe, and provide an empirical example for the study of recalcitrant plant radiations. [Arundinarieae; ddRAD; paleopolyploid; genome skimming; rapid diversification; incongruence.]

The rubber tree, Hevea brasiliensis, produces natural rubber that serves as an essential industrial raw material. Here, we present a high-quality reference genome for a rubber tree cultivar GT1 using single-molecule real-time sequencing (SMRT) and Hi-C technologies to anchor the ∼1.47-Gb genome assembly into 18 pseudochromosomes. The chromosome-based genome analysis enabled us to establish a model of spurge chromosome evolution, since the common paleopolyploid event occurred before the split of Hevea and Manihot. We show recent and rapid bursts of the three Hevea-specific LTR-retrotransposon families during the last 10 million years, leading to the massive expansion by ∼65.88% (∼970 Mbp) of the whole rubber tree genome since the divergence from Manihot. We identify large-scale expansion of genes associated with whole rubber biosynthesis processes, such as basal metabolic processes, ethylene biosynthesis, and the activation of polysaccharide and glycoprotein lectin, which are important properties for latex production. A map of genomic variation between the cultivated and wild rubber trees was obtained, which contains ∼15.7 million high-quality single-nucleotide polymorphisms. We identified hundreds of candidate domestication genes with drastically lowered genomic diversity in the cultivated but not wild rubber trees despite a relatively short domestication history of rubber tree, some of which are involved in rubber biosynthesis. This genome assembly represents key resources for future rubber tree research and breeding, providing novel targets for improving plant biotic and abiotic tolerance and rubber production.

In the area of naval architecture and ocean engineering, the research about the underwater explosion problem is of great significance. To achieve prolonged simulation of near-free surface underwater explosion, the underwater explosion transient numerical model is established in this paper based on compressible Eulerian finite element method (EFEM). Compared with Geers–Hunter formula, EFEM is availably validated by simulating the free-field underwater explosion case. Then, the bubble pulsation and flow field dynamic characteristics of the cases with different underwater explosive depth are compared in this work. Lastly, the height of the water hump and the pressure of flow flied are analyzed quantitatively through the simulation results. Keywords: Bubble dynamics, Underwater explosion, Free surface, Eulerian finite element method

A high-pressure oscillating bubble near discontinuous boundaries (composed of a vertical air-backed plate with a circular opening and a free surface) may generate a high-speed water spike through the opening. This phenomenon is relevant to the survivability of the warship and marine structures subject to underwater explosions, needle-free injection, and inkjet printing. The complicated interactions among the oscillating bubble, the water spike through the opening, and the free surface wave are modelled using the dual fast multipole boundary element method. A moving five-point least-squares smoothing scheme is adopted to maintain smoothness of the surface of the opening. Multiple water jets form during the late compression stage of the bubble owing to the influence of the complex boundaries and gravity, and are directed away from the discontinuous boundaries, with the result that the jet may not impact on the broken boundary. The compression of the bubble induces the necking of the water spike passing through the opening and the formation of a cavity in the area near the opening, reducing the amount of water flooding through the opening. Nevertheless, the depth and speed of the flooding water spike due the oscillating bubble can be much larger than those in the natural flooding case (i.e., in the absence of an oscillating bubble). Both the late expansion and the compression stages of the bubble can accelerate the speed of the water spike. In the case of an opening caused by damage to the cabin wall of a marine vessel, such high-speed spikes may have significant effects on structures and facilities inside the cabin, especially for small opening sizes and short distances between bubble and opening. The results also reveal that at large depths, the dynamic behaviour of the water spike is dominated by hydrostatic pressure, and the interaction between bubble and inrushing water becomes weaker.

A new polymer black hole solution in loop quantum gravity was proposed recently. The difference between the polymer black hole and Schwarzschild black hole is captured by a quantum parameter $A$. In order to get the constraints on parameter $A$, we consider the observational constraints imposed on $A$ by using the Solar System experiments and calculate the deflection of light, Shapiro time delay, perihelion precession and obtain the effects associated with parameter $A$. Moreover, the parameterized post-Newtonian approach of this loop quantum gravity black hole was also carried out. It turns out the tightest constraint on $A$ can be improved to $0, Comment: 13 pages, 1 table; revised version, 16 pages, accepted by PRD

The course, tempo and mode of chloroplast genome evolution remain largely unknown, resulting in limited knowledge about how plant plastome gene and genome evolve during the process of recent plant speciation. Here, we report the complete plastomes of 22 closely related Oryza species in chronologically ordered stages and generate the first precise map of genomic structural variation, to our knowledge. The occurrence rapidity was estimated on average to be ~7 insertions and ~15 deletions per Myr. Relatively fewer deletions than insertions result in an increased repeat density that causes the observed growth of Oryza chloroplast genome sizes. Genome-wide scanning identified 14 positively selected genes that are relevant to photosynthesis system, eight of which were found independently in shade-tolerant or sun-loving rice species. psaA seemed positively selected in both shade-tolerant and sun-loving rice species. The results show that adaptive evolution of chloroplast genes makes rice species adapt to diverse ecological habitats related to sunlight preferences.

The shock wave and cavitation are main effects in the far-field underwater explosion, which could cause serious damage to marine structures. In this paper, the fluid mechanical behavior of blast load is described by the propagation of pressure wave. The acoustic pressure caused by far-field explosion is determined by solving the wave equation, where a strongly discontinuous axisymmetric numerical model is established with the local discontinuous Galerkin (LDG) method. The model can calculate the dynamic pressure in the fluid field and capture the high-resolution shock wave. The pressure cutoff model is employed to deal with the cavitation effect due to the reflection of the shock wave. The numerical model is verified by comparing with the analytical solution of the cavitation effect near the structure in one dimension. With the same mesh discretization, the present model shows higher precision than the results calculated by the acoustic finite element method. In addition, the propagation of shock wave in the cylindrical water column is studied. Finally, the formation, growth and collapse of the cavitation region near the free surface are simulated. The LDG model can remove the spurious oscillations behind the shock front and it’s more accurate than the results of the acoustic finite element method, in terms of capturing the sharpness of shock wave and calculating the shock and cavitation loading. And the present model can be applied to calculate the structural damage caused by shock wave in three dimensions.

To explore the effects of arbuscular mycorrhizal fungi (AMF) on the growth of legume crop, pot and field experiments with soybean were conducted. Treatments of inoculation (+AMF) and non-inoculation with AMF (-AMF) were set up for the pot experiment, and AMF mycelium non-limited and limited for the field experiment. Results of the pot experiment showed that inoculation with AMF significantly increased soybean aboveground biomass (16.5%) and root nodules number (131.4%), above-ground plant phosphorus and nitrogen concentrations and uptakes. In the field trial, the above-ground and root biomasses and root nodules number under AMF mycelium non-limited were significantly increased by 123.6%, 61.5%, and 212.5% compared with those under the limited condition, respectively. Plant phosphorus uptake, nitrogen concentration and uptake, and soil available nitrogen and phosphorus concentrations were significantly higher under AMF mycelium non-limited than the limited both in both shoot and root. Our findings provide theoretical reference for further understanding the relationship between legume crop and AMF, as well as the efficient utilization of phosphorus fertilizer.本研究以大豆为材料,采用盆栽和田间试验,探讨丛枝菌根真菌(AMF)对豆科作物生长的影响。盆栽试验设置了接种(+AMF)和不接种(-AMF)丛枝菌根真菌处理,田间试验设置了AMF菌丝非限制与限制处理。盆栽试验结果表明: 接种AMF显著提高了大豆地上部生物量(16.5%)和大豆根瘤数(131.4%),地上部磷含量、磷吸收量、氮含量和氮吸收量也显著增加。田间试验中,AMF菌丝非限制处理下大豆的地上部生物量、根系生物量、根瘤数量分别比限制处理下显著提高了123.6%、61.5%和212.5%,地上部和根系磷吸收量、氮含量、氮吸收量均显著高于限制处理,大豆根际土壤速效氮和有效磷含量也均显著高于限制处理。本研究可为进一步认识豆科作物与AMF的共生关系及田间磷肥高效利用提供理论参考。.

On the basis of the boundary element method and explicit finite element method, a three-dimensional fully coupled model is developed to investigate the interaction between a bubble and an elastic-plastic thin-walled plate. The model can accurately calculate the bubble loading acting on the plate surface and describe the structural motion coupling with the flow field on two sides of the plate. As a result of the elastic-plastic effects of the thin-walled plate, the bubble displays attractive motion, repulsive motion, or splitting.

Panax notoginseng is one of the most widely used traditional Chinese herbs with particularly valued roots. Triterpenoid saponins are mainly specialized secondary metabolites, which medically act as bioactive components. Knowledge of the ginsenoside biosynthesis in P. notoginseng, which is of great importance in the industrial biosynthesis and genetic breeding program, remains largely undetermined. Here we combined single molecular real time (SMRT) and Second-Generation Sequencing (SGS) technologies to generate a widespread transcriptome atlas of P. notoginseng. We mapped 2,383 full-length non-chimeric (FLNC) reads to adjacently annotated genes, corrected 1,925 mis-annotated genes and merged into 927 new genes. We identified 8,111 novel transcript isoforms that have improved the annotation of the current genome assembly, of which we found 2,664 novel lncRNAs. We characterized more alternative splicing (AS) events from SMRT reads (20,015 AS in 6,324 genes) than Illumina reads (18,498 AS in 9,550 genes), which contained a number of AS events associated with the ginsenoside biosynthesis. The comprehensive transcriptome landscape reveals that the ginsenoside biosynthesis predominantly occurs in flowers compared to leaves and roots, substantiated by levels of gene expression, which is supported by tissue-specific abundance of isoforms in flowers compared to roots and rhizomes. Comparative metabolic analyses further show that a total of 17 characteristic ginsenosides increasingly accumulated, and roots contained the most ginsenosides with variable contents, which are extraordinarily abundant in roots of the three-year old plants. We observed that roots were rich in protopanaxatriol- and protopanaxadiol-type saponins, whereas protopanaxadiol-type saponins predominated in aerial parts (leaves, stems and flowers). The obtained results will greatly enhance our understanding about the ginsenoside biosynthetic machinery in the genus Panax.

The grass family (Poaceae) includes all commercial cereal crops and is a major contributor to biomass in various terrestrial ecosystems. The ancestry of all grass genomes includes a shared whole-genome duplication (WGD), named rho (ρ) WGD, but the evolutionary significance of ρ-WGD remains elusive. We sequenced the genome of Pharus latifolius, a grass species (producing a true spikelet) in the subfamily Pharoideae, a sister lineage to the core Poaceae including the (Panicoideae, Arundinoideae, Chloridoideae, Micrairoideae, Aristidoideae, and Danthonioideae (PACMAD) and Bambusoideae, Oryzoideae, and Pooideae (BOP) clades. Our results indicate that the P. latifolius genome has evolved slowly relative to cereal grass genomes, as reflected by moderate rates of molecular evolution, limited chromosome rearrangements and a low rate of gene loss for duplicated genes. We show that the ρ-WGD event occurred approximately 98.2 million years ago (Ma) in a common ancestor of the Pharoideae and the PACMAD and BOP grasses. This was followed by contrasting patterns of diploidization in the Pharus and core Poaceae lineages. The presence of two FRIZZY PANICLE-like genes in P. latifolius, and duplicated MADS-box genes, support the hypothesis that the ρ-WGD may have played a role in the origin and functional diversification of the spikelet, an adaptation in grasses related directly to cereal yields. The P. latifolius genome sheds light on the origin and early evolution of grasses underpinning the biology and breeding of cereals.

In this work ice breaking caused by a pair of interacting collapsing bubbles was studied by an experimental approach. The bubbles were generated by an underwater electric discharge simultaneously, positioned either horizontally or vertically below a floating ice plate and observed via high-speed photography. The bubble-induced shock waves, which turn out to be crucial to the fracturing of the ice, were visualized using a shadowgraph method and also measured using pressure transduces. Unique bubble behaviour was observed, including bubble coalescence, bubble splitting, inclined counter-jets and asymmetric toroidal bubble collapse. Bubble dynamic properties, such as jet speed, jet energy and bubble centre displacement, were measured. Shock wave emission and ice breaking capability of the two bubbles were investigated over a range of inter-bubble and bubble–boundary distances. Regions where the damaging potential of the bubble pair are strengthened or weakened were summarized and possible reasons for the variation in the ice breaking capability were analysed based on bubble morphology, jet characteristics and shock wave pressure. The findings may contribute to more efficient ice breaking and also inspire new ways to manipulate cavitation bubble damage.

Oryza rufipogon and O. longistaminata are important wild relatives of cultivated rice, harboring a promising source of novel genes for rice breeding programs. Here, we present de novo assembled draft genomes and annotation of O. rufipogon and O. longistaminata. Our analysis reveals a considerable number of lineage‐specific gene families associated with the self‐incompatibility (SI) and formation of reproductive separation. We show how lineage‐specific expansion or contraction of gene families with functional enrichment of the recognition of pollen, thus enlightening their reproductive diversification. We documented a large number of lineage‐specific gene families enriched in salt stress, antifungal response, and disease resistance. Our comparative analysis further shows a genome‐wide expansion of genes encoding NBS‐LRR proteins in these two outcrossing wild species in contrast to six other selfing rice species. Conserved noncoding sequences (CNSs) in the two wild rice genomes rapidly evolve relative to selfing rice species, resulting in the reduction of genomic variation owing to shifts of mating systems. We find that numerous genes related to these rapidly evolving CNSs are enriched in reproductive structure development, flower development, and postembryonic development, which may associate with SI in O. rufipogon and O. longistaminata.

Exploiting novel gene sources from wild relatives has proven to be an efficient approach to advance crop genetic breeding efforts. Oryza granulata, with the GG genome type, occupies the basal position of the Oryza phylogeny and has the second largest genome (~882 Mb). As an upland wild rice species, it possesses renowned traits that distinguish it from other Oryza species, such as tolerance to shade and drought, immunity to bacterial blight and resistance to the brown planthopper. Here, we generated a 736.66-Mb genome assembly of O. granulata with 40,131 predicted protein-coding genes. With Hi-C data, for the first time, we anchored ~98.2% of the genome assembly to the twelve pseudo-chromosomes. This chromosome-length genome assembly of O. granulata will provide novel insights into rice genome evolution, enhance our efforts to search for new genes for future rice breeding programmes and facilitate the conservation of germplasm of this endangered wild rice species., Measurement(s)DNA • RNA • transcriptome • genome coverage • sequence_assembly • sequence feature annotationTechnology Type(s)DNA sequencing • RNA sequencing • flow cytometry method • computational modeling technique • sequence assembly process • sequence annotationSample Characteristic - OrganismOryza granulata Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12063198

BACKGROUND The treatment protocol for children with developmental dysplasia of the hip (DDH) is routinely adjusted by assessing the hip reduction after 3 weeks of Pavlik harness treatment. However, there is a high risk of failure and complications in the treatment adjustment. The aim of this study was to explore the value of ultrasound features in predicting the treatment outcome of Pavlik harness after 3 weeks in DDH children. METHODS A total of 215 DDH children were recruited and the demographics and the changes of ultrasound features [α and β angle and femoral head coverage (FHC)] during the Pavlik harness treatment were recorded. The children were divided into the success group and the failure group according to the reduction outcome after 3 weeks. Univariate and multivariate analyses were performed to analyze the independent predictors for the treatment outcome. Repeated-measures analysis of variance was used to compare the changes of ultrasound features between the two groups during the treatment. Receiver operating characteristic (ROC) curves were plotted to analyze the predictive accuracy of the ultrasound features. RESULTS Graf type III (P=0.036), bilateral dislocation (P=0.031), and age at diagnosis (P=0.021) were associated with an increased risk of Pavlik harness failure in the multivariate analysis. The changes in α and β angle and FHC were generally greater in the success group than in the failure group. The α angle and FHC were larger in the success group, while the β angle was larger in the failure group (P

Energy dissipation mechanisms of bubble pulsation in compressible fluids have always been a significant aspect of research into bubble dynamics. In this paper, bubble dynamics in compressible fluids are investigated numerically with the Eulerian finite-element method (EFEM), and the energy dissipation due to the wave effects of the compressible surrounding fluid is analyzed. The present model is validated by comparing with experimental results. Results from both the simulation and experiment show that bubble fragmentation also contributes to the energy dissipation, which has seldom been discussed before. It is also shown that the initial discontinuity is significant to the energy dissipation which is non-trivial to simulate in 1-dimensional bubble dynamics equations like the Gilmore equation. Then, the relationship between dissipated energy and bubble maximum radii in adjacent pulsating cycles is formulated to quantitatively evaluate the energy dissipation during a pulsating cycle. At last, based on the linearized theory of the energy conservation of the bubble system, a new non-dimensional parameter M a is modified from the Mach number to represent the energy dissipation due to wave effects. With simulation and discussion on cases with different initial pressure and sound speed, it is found that the dissipated energy is related linearly to M a , which can be used to predict the energy dissipation of a new case.

Underwater explosion is an extremely complex hydrodynamic problem and it is always divided into two stages and studied individually, i.e., shock wave stage and bubble motion stage. Actually underwater explosion is a continuous process and there are intensive interactions between the two stages in some cases, e.g. underwater explosion in the vicinity of the wall. In this paper, the Eulerian finite element formulation considering the fluid compressibility is applied to continuously simulate the process of underwater explosion based on the subroutine of ABAQUS. Firstly, the governing equation and its solution by the operator splitting approach are discussed. Then the free-field underwater explosion is continuously simulated, including shock wave propagation and the bubble expansion, contraction, collapse, jet and rebound. The applicability and reliability of this method are discussed by comparing with experimental results from Klaseboer [5]. Furthermore, the traditional treatments of the simulation initialized at the bubble motion stage are discussed. Finally, the underwater explosion near wall is investigated regarding the interactions of shock wave and bubble motion and the importance of the continuous simulation of underwater explosion on the bubble motion characteristics is summarized.

Underwater explosion in free field is investigated in this paper numerically. With the multiphase interface captured by the Volume of Fluid (VOF) method, the Eulerian finite element method (EFEM) for underwater explosion is established. The MUSCL algorithm to advect the element centered variables is modified to maintain its conservativeness in the axisymmetric model, and the second order Early Time Approximation (ETA2) is adopted to deal with the non-reflecting boundary condition of the computational domain. By comparing with the experiment results, the numerical model is proved in both shockwave and bubble oscillation simulation. With the numerical model, 2 underwater explosion cases with different initial depths are simulated and the near-field pressure characteristics are analyzed. The near-field bubble pulsation load exhibits noteworthy asymmetry around the bubble, which is attributed to the 2 high pressure regions above and beneath the bubble, respectively. By comparing the evolution of bubbles with different buoyancy parameters, it is found that the increase of the buoyancy parameter can delay the penetration and extend the collapse of the bubble.

Tea plant is an important economic crop, which is used to produce the world's oldest and most widely consumed tea beverages. Here, we present a high-quality reference genome assembly of the tea plant (Camellia sinensis var. sinensis) consisting of 15 pseudo-chromosomes. LTR retrotransposons (LTR-RTs) account for 70.38% of the genome, and we present evidence that LTR-RTs play critical roles in genome size expansion and the transcriptional diversification of tea plant genes through preferential insertion in promoter regions and introns. Genes, particularly those coding for terpene biosynthesis proteins, associated with tea aroma and stress resistance were significantly amplified through recent tandem duplications and exist as gene clusters in tea plant genome. Phylogenetic analysis of the sequences of 81 tea plant accessions with diverse origins revealed three well-differentiated tea plant populations, supporting the proposition for the southwest origin of the Chinese cultivated tea plant and its later spread to western Asia through introduction. Domestication and modern breeding left significant signatures on hundreds of genes in the tea plant genome, particularly those associated with tea quality and stress resistance. The genomic sequences of the reported reference and resequenced tea plant accessions provide valuable resources for future functional genomics study and molecular breeding of improved cultivars of tea plants.