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Extreme weather patterns and unsustainable development dynamics have substantially increased disaster risks compelling widespread demand for community resilience worldwide. This study aims to develop and measure Risk-integrated Resilience (RiR) index of flood-affected downstream communities in West Rapti Basin (WRB) of the Nepal Himalaya. The evidence-based RiR framework being developed here links risk factor with capital-based resilience characteristics. Three levels of risk zones were categorized based on the flood inundation level considering the latest highest river discharge (7643 m3/s) that the community experienced in 2014. The low-risk zone (≤ 1 foot), moderate-risk zone (> 1 foot to < 5 feet) and high-risk zone (≥ 5 feet) were integrated with five capital domains of resilience characteristics: human, social, economic, physical and natural. Data were acquired through the questionnaire survey from 156 residents, and 61 indicators were finalized for the resilience assessment (r > 0.80; α = 0.85). Shannon entropy-based quantitative method was adopted to assign weight for each indicator. The resilience index was estimated in each capital domain, and finally the composite resilience index was determined in all three risk zones: low-risk zone = 0.358; moderate-risk zone = 0.365; and high-risk zone = 0.295. The result suggests that disaster risk reduction interventions in WRB should focus on improving the lower level of resilience, while low-risk zone should not be neglected. The study highlights that resilience assessment linking risk factors in basin scale is significant approach to reduce the negative impact of flood disasters. The new perspective, evidence-based RiR framework, value adds to effectively and efficiently address the disaster challenges in river basin scale. [ABSTRACT FROM AUTHOR]

The excellent bonding performance between polyester fibers and rubber is key to the high elasticity and fatigue resistance of rubber composite materials. Here, the modified polyester staple fiber (MPET) was obtained by microwave irradiation and surface modification with γ-aminopropyltriethoxysilane (KH550). The results revealed that KH550 reacted with the carboxyl groups on the surface of PET and thus adhered to the fiber surface, which was beneficial in improving compatibility with rubber. When reinforcing natural rubber (NR), MPET combined with the NR molecular chain flexibility due to the rigidity of its own main chain structure. This synergy resulted in the formation of inter-chain entanglements, contributing to a reduction in internal energy dissipation and heat generation within the composite. As the MPET dosage is augmented, the maximum torque of the NR compound during the mixing process exhibits an upward trend. In parallel, the cured NR rubber experiences a gradual reduction in both tensile strength and elongation at break, accompanied by a progressive increase in hardness. Furthermore, a notable elevation in tear strength is observed. This observed trajectory accentuates the intricate interplay between the dosage of MPET and the mechanical attributes of the NR rubber composite. The results of Rubber Processing Analyzer (RPA), Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscope (SEM) indicate that the interfacial bonding between MPET and NR shows promising prospects as rigid short fibers for reinforcing non-polar rubber. [ABSTRACT FROM AUTHOR]

One of the most common and severe natural hazards, flood has been intensified by anthropogenic climate change in many mountain regions affecting socioeconomic conditions during the twenty-first century. The study synthesized the past 50 years (1971–2020) flood loss data; then generated district-wise flood loss spatial maps and explored flood loss mitigation gaps in diverse topography of Nepal Himalaya through literature reviews. Over the past 50 years, on an average, all disasters together caused two deaths per day while more than 300 families got affected daily in Nepal. The proportion of flood disaster alone found 11.43% flood occurrences, 9.33% fatalities, 38.42% missing, 0.75% injury, 61.60% family suffering, and 10.16% property damages. Compared to the 1970s, the number of flood occurrence has increased to more than six folds causing four times human fatalities in the post 2000s. While acknowledging the population growth, the flood loss still shows increasing trend, but the incremental rate is found reduced to almost half. District-wise flood loss spatial maps depict the highest number of flood occurrences in Jhapa while Sarlahi, Surkhet, Chitwan, Mahottari, Sunsari, and Bardiya districts experienced the highest number of peoples' fatalities, missing, injuries, family suffering, fully and partially damages of privately-owned houses, respectively. Although proactive legislations are promulgated, our study found no subsequent reduction in flood loss arguing no progression in holistic flood risk management in Nepal. Our synthesis and identified research gaps highlight the urgent need for adopting evidence-based basin-scale approach to develop effective and sustainable flood mitigation measures. [ABSTRACT FROM AUTHOR]

Short instrumental streamflow records in the South and East Tibetan Plateau (SETP) limit understanding of the full range and long-term variability in streamflow, which could greatly impact freshwater resources for about one billion people downstream. Here we reconstruct eight centuries (1200−2012 C.E.) of annual streamflow from the Monsoon Asia Drought Atlas in five headwater regions across the SETP. We find two regional patterns, including northern (Yellow, Yangtze, and Lancang-Mekong) and southern (Nu-Salween and Yarlung Zangbo-Brahmaputra) SETP regions showing ten contrasting wet and dry periods, with a dividing line of regional moisture regimes at ~32°−33°N identified. We demonstrate strong temporal nonstationarity in streamflow variability, and reveal much greater high/low mean flow periods in terms of duration and magnitude: mostly pre-instrumental wetter conditions in the Yarlung Zangbo-Brahmaputra and drier conditions in other rivers. By contrast, the frequency of extreme flows during the instrumental periods for the Yangtze, Nu-Salween, and Yarlung Zangbo-Brahmaputra has increased by ~18% relative to the pre-instrumental periods. A new study reconstructs eight-century streamflow over the South and East Tibetan Plateau, showing that observations underestimate the full range of long-term streamflow variability and revealing contrasting regional variability in streamflow between south and north study regions. [ABSTRACT FROM AUTHOR]

River dams provide many benefits, including flood control. However, due to constantly evolving channel morphology, downstream conveyance of floodwaters following dam closure is difficult to predict. Here, we test the hypothesis that the incised, enlarged channel downstream of dams provides enhanced water conveyance, using a case study from the lower Yellow River, China. We find that, although flood stage is lowered for small floods, counterintuitively, flood stage downstream of a dam can be amplified for moderate and large floods. This arises because bed incision is accompanied by sediment coarsening, which facilitates development of large dunes that increase flow resistance and reduce velocity relative to pre-dam conditions. Our findings indicate the underlying mechanism for such flood amplification may occur in >80% of fine-grained rivers, and suggest the need to reconsider flood control strategies in such rivers worldwide. Dams constructed on fine-grained rivers cause an increase in flow resistance downstream, thereby amplifying, rather than reducing, flood stage. [ABSTRACT FROM AUTHOR]

The drilled and postgrouted concrete pipe (DPG) pile, consisting of a core pile and a grout layer, is a prospective pile foundation proposed in recent years. Its lateral behaviors were investigated and compared with the traditional driven piles by scaled model tests and numerical analyses. The results show that the grout layer is bonded to the core pile and undertakes moments and lateral loads as part of the pile when the lateral load is less than 9.0kN, while cracks at depth 4D and loses most of its ability to undertake moments when the lateral load exceeds 9.6kN. The presence of the grout layer expanded the pile diameter and increased the contact area between pile and soil, and therefore leading to significant decreases in lateral displacement (44.1 to 69.8%) and moment (35.6%), and significant increases in lateral bearing capacity (56.2 to 150%), comparing to the driven piles. Experimental P-y curves for the DPG piles and the driven piles in clay were derived and described by a hyperbolic function defined by the initial stiffness Ki and ultimate soil resistance Pu. For both kinds of piles, the Ki is independent of depth, and the Pu increases with increasing depth and keeps constant at the depth below 1.6 m (10D). However, due to the effects of the grout layer, Ki for the DPG piles is 35.8% greater than the driven piles, and Pu for the DPG pile is 21.1 to 71.9% greater than the driven piles. [ABSTRACT FROM AUTHOR]

The drilled and post-grouted concrete pipe (DPG) pile consisting of a core pile and the surrounding grout layer is a prospective pile foundation proposed in recent years. In this paper, on the example of a pile group located in Suizhou, Hubei, China, the lateral bearing properties of the DPG piles and impact factors, such as the historical compression loads, the core pile prestress, the core pile wall thickness, the grout layer thickness, and the pile-head constrain conditions, were investigated with field tests and three-dimensional finite element analyses. For the analyzed case, the results show that historical compression loads would increase the pile-head lateral displacement by 125.8–287.3% and decrease the lateral bearing capacity by 32.4%. The core pile prestress prevents the pile shaft from cracking, reduces the flexure deformation of pile shaft, and improves the lateral bearing capacity of the DPG pile by 12.9%. The effects of varying the core pile wall thickness on lateral bearing characteristics are negligible. However, the thickness of the grout layer increases from 0 to 100 mm leading to a 27.2% increase in lateral bearing capacity and a 35.3% decrease in pile shaft bending moment. Additionally, constraining the pile-head rotation would improve the lateral bearing capacity by 60.9% and decrease the pile-head displacement by 68.4%. [ABSTRACT FROM AUTHOR]

The influence of load pattern and Poisson' s ratio effect on the pullout performance of the anchor bolt, which were connected with pipe pile by core concrete, were investigated by three anchorage-beam pullout tests and one self-balanced pullout test. Theoretical and finite element analysis were also employed to explore the influence of load pattern and Poisson' s ratio effect on the ultimate friction at the pipe-core-concrete contact surface. The results show that the load pattern and Poisson' s ratio effect of pipe pile have a great influence on the pullout characteristics of the anchor bolt. The maximum relative displacements between core concrete and pipe pile and between anchor bolt and core concrete in self-balanced pullout test are 0.913 mm and 0.935 mm, respectively, which are significantly greater than that in anchorage-beam pullout test where the displacements are 0.292 mm and 0.500 mm, respectively. In the self-balanced test, the pipe pile is under compression and expands radially due to the Poisson' s ratio effect. In the anchorage-beam test, on the contrary, the pipe pile is under tension and shrinks radially. As a consequence, the ultimate friction between core concrete and pipe pile in the anchorage-beam test is higher than that in the self-balanced test by 15.1% to 28.7%. Accordingly, the results of anchorage-beam pullout test are more sensible for the anchor bolt design. [ABSTRACT FROM AUTHOR]

Aiming to fabricate highly flexible conductors via a facile method, hybrid fillers of carbon nanotubes (CNTs) and carbon fiber (CF) were incorporated with polydimethylsiloxane (PDMS) using a solution blending method. The results showed that the hybrid fillers evidently decreased the composite resistivity and the lowest resistivity was achieved with the composite that had 6:4 CNT/CF ratio when the total filler content was 1 wt%. Due to the low filler content, the stretching strains of the composites reached greater than 200%, and the conductive network which was formed by flexible CNT and rigid CF was sensitive to strain and the related resistance change of resulted composites reached 2480.5% with a gauge factor of 50. The alternating current electrical, rheological and morphological property measurements were performed, and the results presented the existence of synergistic effect between the hybrid fillers in the conductive networks which decreased resistivity of composites. Therefore, the PDMS/CNT/CF nanocomposites are good candidates for application as inflexible sensors. [ABSTRACT FROM AUTHOR]

The quantification of the sheltering and exposure effects of non-uniform sediments has been widely achieved through hiding function models. Big challenge exists so far in the model parameter that is highly variable and differs greatly between laboratory flumes and field streams. This paper presents an improved surface-based hiding function. The force balance for particle inception was formulated and the allocation of the overall bed shear stress into each group of sediments was mimicked. The new hiding function was examined against and agrees well with the documented field and flume data. It was shown that the hiding function is closely related to the relative flow depth and the reference elevation in the velocity profile in addition to the bed material gradation. The power law of velocity profile that applies to both flume flows and natural streams can link the flume and field data together. The hiding function with b = 1/6 and b = 1/2 is applicable to natural streams and laboratory flumes, respectively. The value of b = 0.263 also works well for gravel bed rivers. The range of the reference elevation, namely z = 0.4D-1.4D, is recommended for either the flume or field data. The new hiding function contributes to addressing clearer physical meanings and a useful perspective for further improvement. [ABSTRACT FROM AUTHOR]

Hyperalgesia and allodynia are commonly observed in patients with diabetic neuropathy. The mechanisms responsible for neuropathic pain are not well understood. Thus, in this study, we examined the role played by purinergic P2X receptors of the midbrain periaqueductal gray (PAG) in modulating diabetes-induced neuropathic pain because this brain region is an important component of the descending inhibitory system to control central pain transmission. Our results showed that mechanical withdrawal thresholds were significantly increased by stimulation of P2X receptors in the dorsolateral PAG of rats ( n = 12, P < 0.05 vs. vehicle control) using α,β-methylene-ATP (α,β-meATP, a P2X receptor agonist). In addition, diabetes was induced by an intraperitoneal injection of streptozotocin (STZ) in rats, and mechanical allodynia was observed 3 weeks after STZ administration. Notably, the excitatory effects of P2X stimulation on mechanical withdrawal thresholds were significantly blunted in STZ-induced diabetic rats ( n = 12, P < 0.05 vs. control animals) as compared with control rats ( n = 12). Furthermore, the protein expression of P2X receptors in the plasma membrane of the dorsolateral PAG of STZ-treated rats was significantly decreased ( n = 10, P < 0.05 vs. control animals) compared to that in control rats ( n = 8), whereas the total expression of P2X receptors was not significantly altered. Overall, data of our current study suggest that a decrease in the membrane expression of P2X receptors in the PAG of diabetic rats is likely to impair the descending inhibitory system in modulating pain transmission and thereby contributes to the development of mechanical allodynia in diabetes. [ABSTRACT FROM AUTHOR]

This paper presents a generalized framework of stochastic modeling for particle kinetics in wall-bounded flow. We modified a reflected Brownian motion process and straightforwardly obtained a Kramers equation for particle probability density function (PDF). After the wall effects were accounted for as a drift from zero in the mean displacement and suppression in the diffusivity of a particle, an analytical solution was worked out for PDF. Three distinguishable mechanisms were identified to affect the profile of particle probability distribution: external forces, turbophoresis effect, and wall-drift effect. The proposed formulation covers the Huang et al. (2009) model of a wall that produces electrostatic repulsion force and van der Waals force, as well as Monte-Carlo solutions for the Peter and Barenbrug (2002) model under a variety of relaxation times. Moreover, it successfully reproduces the two patterns of particle concentration profiles observed in experiments of sediment-laden open-channel flows. The strength of the wall-drift effect was found to be connected with the interaction frequency between particle and wall. Further exploration of the relationship among flow turbulence, particle inertia, and particle concentration is worthwhile. [ABSTRACT FROM AUTHOR]

An algorithm for simulating free surface flows is presented using large time step based on the wave-propagation method proposed by LeVeque, and an exact Riemann solver is used. A multiple wave approximation approach was suggested for eliminating the discontinuities found in the rarefaction fans of dam-breaking flows. In addition, we use the random choice method to reduce non-physical oscillations. Applications demonstrate that the algorithm proposed in this paper can considerably increase the CFL number up to 25 when modeling dam-break flows, while retaining satisfactory accuracy and efficiency. This suggests that our algorithm has the potential to be applied to modeling free surface flows. [ABSTRACT FROM AUTHOR]

Metabolism and ageing are intimately linked. Compared with ad libitum feeding, dietary restriction consistently extends lifespan and delays age-related diseases in evolutionarily diverse organisms. Similar conditions of nutrient limitation and genetic or pharmacological perturbations of nutrient or energy metabolism also have longevity benefits. Recently, several metabolites have been identified that modulate ageing; however, the molecular mechanisms underlying this are largely undefined. Here we show that ?-ketoglutarate (?-KG), a tricarboxylic acid cycle intermediate, extends the lifespan of adult Caenorhabditis elegans. ATP synthase subunit ? is identified as a novel binding protein of ?-KG using a small-molecule target identification strategy termed drug affinity responsive target stability (DARTS). The ATP synthase, also known as complex V of the mitochondrial electron transport chain, is the main cellular energy-generating machinery and is highly conserved throughout evolution. Although complete loss of mitochondrial function is detrimental, partial suppression of the electron transport chain has been shown to extend C. elegans lifespan. We show that ?-KG inhibits ATP synthase and, similar to ATP synthase knockdown, inhibition by ?-KG leads to reduced ATP content, decreased oxygen consumption, and increased autophagy in both C. elegans and mammalian cells. We provide evidence that the lifespan increase by ?-KG requires ATP synthase subunit ? and is dependent on target of rapamycin (TOR) downstream. Endogenous ?-KG levels are increased on starvation and ?-KG does not extend the lifespan of dietary-restricted animals, indicating that ?-KG is a key metabolite that mediates longevity by dietary restriction. Our analyses uncover new molecular links between a common metabolite, a universal cellular energy generator and dietary restriction in the regulation of organismal lifespan, thus suggesting new strategies for the prevention and treatment of ageing and age-related diseases. [ABSTRACT FROM AUTHOR]

Pidotimod is a synthetic dipeptide with biological and immunological activity in innate immune responses. It has been reported that pidotimod could promote functional maturation of dendritic cells, but little is known about the regulation of macrophages. Recent studies have demonstrated that M1 or M2 polarized macrophages are of great importance for responses to microorganism infection or host mediators. The aim of this study was to determine the effectiveness of pidotimod on mouse bone marrow-derived macrophage polarization and its function. The results showed that pidotimod had no influence on M1-polarized macrophage. While interestingly, a significant increase of M2 marker gene expression (Arg1, Fizz1, Ym1, MR) was observed ( p < 0.01) in IL-4-induced M2 macrophage treated with pidotimod. In addition, cell surface expression of mannose receptor was dramatically enhanced using fluorescence activated cell sorter (FACS) analysis. Furthermore, the function of M2 macrophage was also determinated. The results showed that the supernatant of pidotimod-treated M2 macrophage could increase the migration ( p < 0.05) and enhance the wound closure rate ( p < 0.05) of MLE-12 cells. Collectively, it could be concluded that pidotimod significantly facilitated IL-4-induced M2 macrophage polarization and improves its function. [ABSTRACT FROM AUTHOR]

To conduct a large-scale hydrologic-response and landform evolution simulation at high resolution, a complex physics-based numerical model, the Integrated Hydrology Model (InHM), was revised utilizing cluster parallel computing. The parallelized InHM (ParInHM) divides the simulated area into multiple catchments based on geomorphologic features, and generates boundary-value problems for each catchment to construct simulation tasks, which are then dispatched to different computers to start the simulation. Landform evolution is considered during simulating and implemention in one framework. The dynamical Longest-Processing-Time (LPT) first scheduling algorithm is applied to job management. In addition, a pause-integrate- divide-resume routine method is used to ensure the hydrologic validity during the simulation period. The routine repeats until the entire simulation period is finished. ParInHM has been tested in a computer cluster that uses 16 processors for the calculation, to simulate 100 years' hydrologic-response and soil erosion for the 117-km Kaho'olawe Island in the Hawaiian Islands under two different mesh resolutions. The efficiency of ParInHM was evaluated by comparing the performance of the cluster system utilizing different numbers of processors, as well as the performance of non-parallelized system without domain decomposition. The results of this study show that it is feasible to conduct a regional-scale hydrologic-response and sediment transport simulation at high resolution without demanding significant computing resources. [ABSTRACT FROM AUTHOR]

This study provides evidence that the outcome for shareholders resulting from asset sales is determined at the time of transaction by the value for the asset sold. Assets sold above market value are followed by positive and significant abnormal returns over the following three months; these returns are magnified in firms where the balance of power in corporate governance favors shareholders. Abnormal returns following undervalued asset sales are insignificant from zero, indicating value-preservation. Value-preservation when the assets are sold below market value becomes less likely as firms approach financial constraints. The reverse is true when assets are sold above market value. This evidence is documented for apartment REITs, which have a large number of comparable transactions available for estimating expected market values. [ABSTRACT FROM AUTHOR]

Physically based modeling approach has been widely developed in recent years for simulation of dam failure process resulting from overtopping flow. Due to the lack of field data, there exist few applications to natural quake dams with complex erosion mechanisms. This paper presents a physically based simulation of the failure process of the Tangjiashan Quake Dam formed as a result of the 'May 12, 2008' Wenchuan earthquake in China. The one-dimensional model adopted features as cost saving but enables capturing the main characteristics of the failure process, where selective sediment transport and gravitational slope collapse are accounted for. The simulated flow hydrograph and breach progression process are generally in good agreement with the observed data. Unsteadiness and non-uniformity are found to be substantial characteristics of breach progression during the failure process of natural quake dams. Sensitivity analysis showed that the Manning resistance coefficient and the erodibility coefficient in Osman and Thorne's (J Hydraul Eng 114(2):134-150, ) model significantly influences the flow peak discharge but has less influence on its occurrence time, while the velocity lag coefficient associated with bed-load transport may affect the two breaching parameters substantially. [ABSTRACT FROM AUTHOR]

The massive 8.0-magnitude Wenchuan Earthquake triggered huge landslides, avalanches, and debris flows that blocked rivers and created 34 important quake lakes, including the Tangjiashan Quake Lake on the Tongkou River. More than half of these lakes were identified to be of moderate or high hazard levels, so activities needed to be undertaken for hazard mitigation of potential flooding. This paper presents the mitigation processes of quake lake hazards, which involve various techniques such as rapid hazard analysis, scenario-based mitigation planning, and real-time forecasting of outburst flooding for implementation actions. The shortage of hydrologic and geological data and the nature of emergency situations raise substantial challenges in the hazard mitigation of quake lakes. This paper suggests a potential approach in dealing with quake lake hazards, which integrates the automatic monitoring network, hydrologic models, and hydrodynamic models with a comprehensive indicator for hazard levels. The necessity of improving the integrated methodology is highlighted. [ABSTRACT FROM AUTHOR]

Sediment delivery ratio (SDR) for fluvial rivers was formulated with sediment rating curve. The observed data of SDR on flood event scale of the Lower Yellow River (LYR) were adopted to examine the formulation and to calibrate the model parameters. A regression formula of SDR was then established and its 95% prediction interval was accordingly quantified to represent its overall uncertainties. Three types of factors including diversity of the incoming flow conditions, river self-regulation processes, and human activities were ascribed to the uncertainties. The following were shown: (1) With the incoming sediment coefficient (ISC) being a variable, it was not necessary to adopt the incoming flow discharge as the second variable in the formulation of SDR; and (2) ISC=0.003 and therefore SDR=2 might be a threshold for distinguishing the characteristics of sediment transport within the LYR. These findings would highlight sediment transport characteristics on the scale of flood event and contribute to uncertainty based analysis of water volume required for sediment transport and channel maintenance of the LYR. [ABSTRACT FROM AUTHOR]

A kinetic model was presented for dilute solid-liquid two-phase flows with inelastic collisions by modeling the inelastic collisions with the revised BGK model (Santos and Astillero, 2005) and particle turbulence interactions with the Fokker-Planck operator. The formulated model kinetic equation was solved with the Chapman-Enskog method and the obtained approximate solution was further adopted to derive the constitutive relationships for the conservation equations of the particle phase. The new constitutive relationships would be suitable for the study on dilute solid-liquid two-phase flows such as sediment-laden flows in open channels or rivers. [ABSTRACT FROM AUTHOR]

The homotopy analysis method (HAM), as a new mathematical tool, has been employed to solve many nonlinear problems. As a fundamental equation in non-equilibrium statistical mechanics, the Boltzmann integro-differential equation (BE) describing the movement of particles is of strong nonlinearity. In this work, HAM is preliminarily applied to dilute granular flow which is relatively simple. By choosing the Maxwell velocity distribution function as the initial solution, the concrete expression of the first-order approximate solution to BE with collision term being the BGK model is given. Furthermore it is consistent with the solution using Chapman-Enskog method but does not rely on little parameters. [ABSTRACT FROM AUTHOR]

The Tangjiashan Quake Lake is the largest quake lake triggered by the 5.12 Wenchuan Earthquake that happened on May 12, 2008 in China, posing high risk of catastrophic flash flood hazards to downstream human life and properties. A physics-based numerical simulation approach is proposed for real-time prediction of dam breach development of the Tangjiashan Quake Lake in the case of emergency treatment. Bed erosion and lateral development of the dam breach are represented through accounting for the underlying physics including selective sediment transport and gravitational collapse. Conceptualized breach erosion model that involves few parameters enables quick calibration based on the monitored hydrological data in emergency analysis where fully geotechnical information about the barrier dam is not available. The process of dam breach development is found to be nonlinear in cascades due to the combined effects of headcutting and bank collapse. The agreement between the simulation results and the observed data shows the applicability of the present approach for emergency analysis of quake lakes. Limitations will arise in the situation where the soil composition of barrier dam is significantly inhomogeneous. Incorporation of circular arc failure for cohesive soil and lateral seepage in bank slope will also enhance its applicability to complex situations. [ABSTRACT FROM AUTHOR]

Diffusion coefficient of natural sediments and effects of lift force and gradient in particle velocity fluctuations were investigated through using a closed kinetic model. Comparison against experimental data of Einstein & Chien (1955) validated the model. The diffusion coefficient εyy of medium and large sediments distinctly exceeds fluid eddy viscosity νft, while εyy of fine sediments approximately equals νft. In the measured region of 0.03

Starting with the kinetic theory for dilute solid/liquid two-phase flow, a mathematical model is established to predict the flow in a horizontal square pipe and the predictions are compared with LDV measurements. The present model predicts correctly two types of patterns of the vertical distribution of particle concentration observed in experiments, and also gives different patterns of the distribution of particle fluctuating energy. In the core region of the pipe, the predicted mean velocity of particles is smaller than that of liquid, but near the pipe bottom the reverse case occurs. In addition, full attention is paid to the mechanism for the vertical distribution of the average properties of particles such as concentration and mean velocity. From the kinetic-theory point of view, the cause of formation for different patterns of the vertical concentration distribution is not only related to the lift force exerted on a particle, but also related to the distribution of particle fluctuating energy. [ABSTRACT FROM AUTHOR]

The significant use of platinum for catalyzing the cathodic oxygen reduction reactions (ORRs) has hampered the widespread use of polymer electrolyte membrane fuel cells (PEMFCs). The construction of well-defined electrode architecture in nanoscale with enhanced utilization and catalytic performance of Pt might be a promising approach to address such barrier. Inspired by the highly efficient catalytic processes in enzymes with active centers embedded in charge transport pathways, here we demonstrate for the first time a design that allocates platinum nanoparticles (Pt NPs) at the boundaries with dual-functions of conducting both electrons by aid of polypyrrole and protons via Nafion® ionomer within hierarchical nanoarrays. By mimicking enzymes functionally, an impressive ORR activity and stability is achieved. Using this brand new electrode architecture as the cathode and the anode of a PEMFC, a high mass specific power density of 5.23 W mg−1Pt is achieved, with remarkable durability. These improvements are ascribed to not only the electron decoration and the anchoring effects from the Nafion® ionomer decorated PPy substrate to the supported Pt NPs, but also the fast charge and mass transport facilitated by the electron and proton pathways within the electrode architecture. [ABSTRACT FROM AUTHOR]

During early mammalian embryogenesis, changes in cell growth and proliferation depend on strict genetic and metabolic instructions. However, our understanding of metabolic reprogramming and its influence on epigenetic regulation in early embryo development remains elusive. Here we show a comprehensive metabolomics profiling of key stages in mouse early development and the two-cell and blastocyst embryos, and we reconstructed the metabolic landscape through the transition from totipotency to pluripotency. Our integrated metabolomics and transcriptomics analysis shows that while two-cell embryos favour methionine, polyamine and glutathione metabolism and stay in a more reductive state, blastocyst embryos have higher metabolites related to the mitochondrial tricarboxylic acid cycle, and present a more oxidative state. Moreover, we identify a reciprocal relationship between α-ketoglutarate (α-KG) and the competitive inhibitor of α-KG-dependent dioxygenases, L-2-hydroxyglutarate (L-2-HG), where two-cell embryos inherited from oocytes and one-cell zygotes display higher L-2-HG, whereas blastocysts show higher α-KG. Lastly, increasing 2-HG availability impedes erasure of global histone methylation markers after fertilization. Together, our data demonstrate dynamic and interconnected metabolic, transcriptional and epigenetic network remodelling during early mouse embryo development., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)