Rapid Recycling Research Articles

Density Functional Theory Study of Oil-Immersed Transformers Characteristic Decomposition Products Adsorption on n ZrO2 (n = 1~2) Modified GaN Nanotubes

Oil-immersed transformers, with safe reliability and high utilization, plays an irreplaceable role in power transmission and transformation. Unavoidable insulation defects can occur that affect the safety of the power system and socio-economic, thus timely online monitoring becomes a focus of attention in the power sector. In this study, n ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (n = 1-2) modified GaN nanotubes are firstly proposed as a novel gas-sensing material for estimating the discharge faults in oil-immersed transformers through dissolved gas analysis. Density functional theory calculations are carried out to deeply explore the characteristic dissolved gases adsorption and sensing mechanisms. The density of states, charge density difference, band structures, and theoretical recovery time are analyzed to evaluate the feasibility and applicability of the gas sensor. The data shows that ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> dopant provides active sites for gas adsorption. n ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -GaNNTs (n = 1-2) has limited gas sensitivity to H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> but demonstrates considerable ability to capture C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . Moreover, all adsorption has excellent gas-sensitive recovery properties, aiding in the rapid recycling of sensors. Meanwhile, the verification is carried out by experiments. Results in this work can be employed for practical production of n ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (n = 1-2) modified GaN nanotubes gas sensors, ultimately realizing online monitoring of oil-immersed transformer.

Preparation and performance of magnetic phase change microcapsules with organic-inorganic double shell

Magnetic microcapsulated phase change materials can achieve rapid magnetic localization temperature regulation and magnetic separation recycling. However, the efficient encapsulation of both inorganic magnetic material and organic phase change material is a challenge due to their poor compatibility. In this work, an aqueous dispersion containing methylol melamine and sodium alginate loaded with magnetic Fe 3 O 4 nanoparticles (SA-Fe 3 O 4 ) was prepared and mixed with a paraffin emulsion. After methylol melamine was initiated to in-situ polymerize at the interface of the paraffin emulsion droplets, primary magnetic phase change microcapsules (P-MPCM) composed of a paraffin core and SA-Fe 3 O 4 /melamine formaldehyde resin composite shell were formed. Then, SiO 2 sol particles were adsorbed on the surface of P-MPCM to form the final MPCM with a polymer-SiO 2 double-shell (PS-MPCM). The magnetic polymer-SiO 2 double-shell endows the PS-MPCM with rapid magnetic responsiveness (can be quickly collected under magnetic fields), high phase change enthalpy (184.4 J·g-1) and excellent structural stability. The phase change enthalpy and saturation magnetization of PS-MPCM have changed little after 200 thermal cycles. At the same time, the excellent photothermal conversion efficiency (93.9%) of PS-MPCM benefits for solar energy conversion utilization in actual application. This work provides a new way to obtain MPCM with high thermal conductivity (0.64 W·m-1·K-1), rapid magnetic response and excellent reusability, which can be potentially applied for directional temperature regulation. Magnetic polymer-SiO 2 double-shell phase change microcapsule (PS-MPCM) was prepared. PS-MPCM exhibits high encapsulation ratio of paraffin and Fe 3 O 4 nanoparticles (NPs). Sodium alginate was introduced to achieve efficient and stable loading of Fe 3 O 4 NPs. PS-MPCM exhibits excellent thermal conductivity, magnetic response and reusability. PS-MPCM can be potentially applied for magnetic localization temperature regulation.

Stable silicon isotopes uncover a mineralogical control on the benthic silicon cycle in the Arctic Barents Sea

Biogeochemical cycling of silicon (Si) in the Barents Sea is under considerable pressure from physical and chemical changes, including dramatic warming and sea ice retreat, together with a decline in dissolved silicic acid (DSi) concentrations of Atlantic inflow waters since 1990. Associated changes in the community composition of phytoplankton blooms will alter the material comprising the depositional flux, which will subsequently influence recycling processes at and within the seafloor. In this study we assess the predominant controls on the early diagenetic cycling of Si, a key nutrient in marine ecosystems, by combining stable isotopic analysis (δ30Si) of pore water DSi and of operationally defined reactive pools of the solid phase. We show that low biogenic silica (BSi) contents (0.26–0.52 wt% or 92–185 μmol g dry wt−1) drive correspondingly low asymptotic concentrations of pore water DSi of ∼100 μM, relative to biosiliceous sediments (>20 wt% BSi) wherein DSi can reach ∼900 μM. While Barents Sea surface sediments appear almost devoid of BSi, we present evidence for the rapid recycling of bloom derived BSi that generates striking transient peaks in sediment pore water [DSi] of up to 300 μM, which is a feature that is subject to future shifts in phytoplankton community compositions. Using a simple isotopic mass balance calculation we show that at two of three stations the pore water DSi pool at 0.5 cm below the seafloor (+0.96 to +1.36 ‰) is sourced from the mixing of core top waters (+1.46 to +1.69 ‰) with the dissolution of BSi (+0.82 to +1.50 ‰), supplemented with a lithogenic Si source (LSi) (−0.89 ±0.16‰). Further, our sediment pore water δ30Si profiles uncover a coupling of the Si cycle with the redox cycling of metal oxides associated with isotopically light Si (−2.88 ±0.17‰). We suggest that a high LSi:BSi ratio and apparent metal oxide influence could lead to a degree of stability in the annual background benthic flux of DSi, despite current pressures on pelagic phytoplankton communities. Coupled with supporting isotopic evidence for the precipitation of authigenic clays in Barents Sea sediment cores, our observations have implications for the regional Si budget.

Membrane Phosphoinositides Stabilize GPCR‐arrestin Complexes and Provide Temporal Control of Complex Assembly and Dynamics

Binding of arrestin to phosphorylated G protein‐coupled receptors (GPCRs) is crucial for gating signaling. Once internalized some GPCRs remain stably associated with arrestin, while others interact transiently; this difference affects signaling and recycling behaviors of these GPCRs. Using cell‐based and in vitro biophysical assays we examined the role of membrane phosphoinositides (PIPs) in arrestin recruitment and GPCR‐arrestin complex dynamics. We find that GPCRs broadly stratify into two groups, one which requires PIP‐binding for arrestin recruitment and one that does not. Plasma membrane PIPs potentiate an active conformation of arrestin and stabilize GPCR‐arrestin complexes by promoting a core‐engaged state of the complex. As allosteric modulators of GPCR‐arrestin complex dynamics, membrane PIPs allow for additional conformational diversity beyond that imposed by GPCR phosphorylation alone. The dependance on membrane PIPs provides a mechanism for arrestin release from transiently associated GPCRs, allowing their rapid recycling, while explaining how stably associated GPCRs are able to engage G proteins at endosomes.

Temporal variability of plutonium in surface waters of the Sea of Japan

Long-term temporal variations of plutonium in Sea of Japan (SOJ) surface waters have been examined with the aim to better understand its behavior during several decades. The first observation is that 239,240Pu activity concentrations in surface waters of the SOJ during 1977–2019 were 6.5 ± 4.7 mBq m−3 in average, and 5.1 mBq m−3 as the median, whereas 137Cs and 90Sr activity concentrations decreased with time, except of the perturbation due to the 2011 Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Another observation is that sporadic high 239,240Pu activity concentrations occurred in the east Japan Basin, ranging from 1 to 39 mBq m−3. The spatial distribution of 239,240Pu activity concentrations in surface waters revealed that high 239,240Pu levels (>20 mBq m−3) occurred in 1994 in the northern SOJ, which was considered to be due to winter convection. To elucidate factors controlling the temporal variability of surface 239,240Pu levels in the SOJ, a relationship between surface 239,240Pu activity concentrations and vertical diffusion coefficients was examined. The results revealed that this relationship could be classified into two groups: one group did not show a change with increasing diffusion coefficient, while the other group showed a positive correlation. The vertical 239,240Pu distribution in SOJ waters suggests that the high surface 239,240Pu levels occurred due to the upwelling of cyclonic eddy. The rapid recycling of deeper plutonium occurred in the SOJ due to deep winter convection and upwelling associated with cyclonic eddy. The plutonium levels in the SOJ have been found to be sensitive to climate changes. Warming of the SOJ may cause a reduction of winter convection and eddy activity as a result of increasing sea surface temperature. This leads to a decline of recirculation of plutonium and other bioavailable elements from Japan Sea Proper Water (JSPW) to surface water layers. Plutonium would be, therefore, an important indicator of biogeochemical processes in the marine environment, helping to assess climate change impacts on marine ecological systems.

Rapid and selective recycling of Ag(I) from wastewater through an allylrhodanine functionalized micro-filtration membrane

Balance between membrane flux and ion rejection rate of filtration membranes is an important crucial technology to achieve an efficient wastewater treatment. In this work, a polyvinylidene fluoride (PVDF) with 3-allylrhodanine (3-AR) modified composite 3-AR/PVDF membrane was fabricated by non-solvent induced phase separation method. Some parameters, such as water flux, selectivity and rejection, were investigated during the membrane treatment. Morphology characterizations, such as scanning electron microscope (SEM), nitrogen adsorption–desorption and contact angle techniques confirmed 3-AR/PVDF had hydrophilic surface and uniform porous structure with average pore size about 65.67 ∼ 39.32 nm. Surface chemical structure characterizations, such as Fourier transformed infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) uncovered that the retention of Ag+ was mainly relied on the chemical bonding of C = S and C-S groups on 3-AR. 3-AR/PVDF-0.130 membrane exhibited excellent performance in adsorption (46.42 mg cm−2), water flux (196.04 L m-3 h−1), rejection (8.75 mg), and selectivity (β > 10). Membrane thickness exhibited good linear relationships with water flux and interception (R2 > 0.94), which could be regulated by the thickness of membrane. The membranes maintained excellent stability in wide pH range 1 ∼ 5, and retained >95% rejection and water flux after 6 cycles. Most important, the costs of membrane and operation were assessed during the long-term filtration, which is of significance for practical applications.

Effect of early strength anti-cracking materials on drying shrinkage of recycled cement stabilized macadam

ABSTRACT The increasing road maintenance projects lead to a large amount of construction waste and long-term closed traffic, enabling a rigid demand for early strength recycled cement-stabilized macadam (ERCSM), which can achieve rapid cold recycling. Given that ERCSM is prone to early drying shrinkage cracking, this study aimed to reduce the occurrence of early drying shrinkage cracking by adding early strength anti-cracking materials (EAMs). Therefore, a drying shrinkage test of cement mortar was carried out to determine the types, contents of anti-cracking materials, and their mixing proportions with early strength composite materials. The effect of EAM on the drying shrinkage of ERCSM was also studied. The results show that the anti-cracking material E1 has better crack resistance. Two types of EAMs (M1 and M2) composed of E1 and different early strength composite materials, were determined. EAM could reduce the drying shrinkage of the recycled cement-stabilized macadam base, and M2 had a better resistance to early shrinkage. After adding M2, the total drying shrinkage coefficient at 2 and 3 d decreased by 91.7% and 74.7% compared with the control group, respectively. Microscopic test show M2 can accelerate the hydration process of cement and promote the formation of expansion products at early ages.

Recyclable, malleable and intrinsically flame-retardant epoxy resin with catalytic transesterification

Flame retardancy and recyclability are two important issues in the research field of thermosets, particularly for epoxy resin (EP) with the biggest market share. It is of great importance, but rarely achievable, to integrate these properties simultaneously into EP. Herein, we report a facile way to prepare intrinsically flame-retardant epoxy vitrimers combining rapid recycling and multiple shape memory effects by introducing dynamic ester-linkages with catalytic transesterification activity into the crosslinking networks of EP. The flame-retardant epoxy vitrimers exhibited high Tg (∼110.7 °C), desirable thermal stability and excellent flame retardancy with UL-94 V-0 rating, and high LOI of ∼34%. Also, the value of the peak heat release rate (PHRR) and the total heat release (THR) showed 63% and 32% reduction, respectively. Meanwhile, flame-retardant epoxy vitrimers showed high malleability that could be reprocessed in 15 min at 200 °C without sacrificing the mechanical properties and flame retardancy. Moreover, the dynamic transesterification network allowed flame-retardant EP to access multiple shape memory effect. The design of flame-retardant epoxy vitrimers provide a prime example to foster the cyclic utilization of flame-retardant thermosetting polymers.

Calmodulin Domain Protein Kinase PiCDPK1 Regulates Pollen Tube Growth Polarity through Interaction with RhoGDI.

The pollen-specific calcium-dependent protein kinase PiCDPK1 of Petunia inflata has previously been shown to regulate polarity in tip growth in pollen tubes. Here we report the identification of a Rho Guanine Dissociation Inhibitor (PiRhoGDI1) as a PiCDPK1 interacting protein. We demonstrate that PiRhoGDI1 and PiCDPK1 interact in a yeast 2-hybrid assay, as well as in an in vitro pull-down assay, and that PiRhoGDI1 is phosphorylated by PiCDPK1 in vitro. We further demonstrate the PiRhoGDI1 is capable of rescuing the loss of growth polarity phenotype caused by over-expressing PiCDPK1 in vivo using stable transgenic plants. We confirmed that PiRhoGDI1 interacts with a pollen-expressed ROP GTPase isoform consistent with the established role of RhoGDIs in negatively regulating GTPases through their membrane removal and locking them in an inactive cytosolic complex. ROP is a central regulator of polarity in tip growth, upstream of Ca2+, and PiCDPK1 over-expression has been previously reported to lead to dramatic elevation of cytosolic Ca2+ through a positive feedback loop. The discovery that PiCDPK1 impacts ROP regulation via PiRhoGDI1 suggests that PiCDPK1 acts as RhoGDI displacement factor and leads us to propose a model which we hypothesize regulates the rapid recycling of ROP GTPase at the pollen tube tip.

Facile preparation of reprocessable and degradable phenolic resin based on dynamic acetal motifs

Phenolic resins with irreversible cross-links structure make them difficult to degrade and recycle. It is an emerging trend for phenolic resins thermoset to develop a rapid and facile closed-loop recycling approach. Herein, the degradable and reprocessable phenolic thermosets (PRTs) based on reversible acetal bonds were synthesized by tri(ethylene glycol) divinyl ether (TEGDVE) and linear phenolic resin through one-step “click” addition reaction. By employing the chain mobility induced by dynamic weak acetal motifs and linear TEGDVE in PRTs, the mechanical strengths could be rationally adjusted, and more moderate reprocessing and degradation conditions were achieved. Accordingly, the flexible structure units containing weak reversible acetal linkages were expected to accelerate the mobility of the chain segments and decrease the reprocessing temperature, while the linear phenolic structure afforded the high mechanical strength. Remarkedly, a champion degradation rate of 121.8 mg·mL−1·h−1 was achieved under acid condition by adjusting the ratio of flexible chains consisting of dynamic acetal bonds. In addition, compared with pristine PRTs, regenerative one maintained 93.41% of elongation at break. This work may shed a light for realizing degradable and reprocessable dynamic network materials with high efficiency.

Quantification of AMPA-type glutamate receptors trafficking by ligand-directed two-step labeling

Glutamate receptors mediate excitatory neurotransmission in the central nervous system, which have essential roles in our learning and memory. Recent studies have revealed that the trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA)-type glutamate receptors (AMPA receptors) are dynamically regulated during synaptic plasticity, the cellular basis of learning and memory. Conventionally, biochemical methods such as surface-biotin labeling or genetic incorporation of fluorescent proteins have been utilized to analyze the AMPA receptors dynamics. However, conflicting findings have been reported because of serious issues in these conventional methods. As the alternative, we have developed a new method for labeling AMPA receptors endogenously expressed in neurons by chemical approaches. This is based on a covalent chemical labeling strategy driven by selective ligand-protein recognition to tether small fluorophores to the target receptors, termed ligand-directed acyl imidazole chemistry. This method has successfully visualized AMPA receptors endogenously expressed in neurons. However, the original method required several hours for fluorophore labeling, which hampered analyzing the dynamics of AMPA receptors in detail. As the alternative, we have recently developed an improved strategy for rapid and selective labeling of chemical probes to cell-surface AMPA receptors by combining ligand-directed chemistry and bio-orthogonal click chemistry. This method allowed to quantify their trafficking, which revealed unique features of AMPA receptors such as long lifetime and rapid recycling in neurons. Notably, this method can be expanded to other receptors. Thus, the two-step labeling method would be a useful tool for understanding the physiological or pathophysiological roles of glutamate receptors in neurons.

Rapid and Selective Recycling of Ag(I) from Wastewater Through an Allylrhodanine Functionalized Micro-Filtration Membrane

Rapid and Selective Recycling of Ag(I) from Wastewater Through an Allylrhodanine Functionalized Micro-Filtration Membrane

A Replication-Competent HIV Clone Carrying GFP-Env Reveals Rapid Env Recycling at the HIV-1 T Cell Virological Synapse.

HIV-1 infection is enhanced by cell–cell adhesions between infected and uninfected T cells called virological synapses (VS). VS are initiated by the interactions of cell-surface HIV-1 envelope glycoprotein (Env) and CD4 on target cells and act as sites of viral assembly and viral transfer between cells. To study the process that recruits and retains HIV-1 Env at the VS, a replication-competent HIV-1 clone carrying an Env-sfGFP fusion protein was designed to enable live tracking of Env within infected cells. Combined use of surface pulse-labeling of Env and fluorescence recovery after photobleaching (FRAP) studies, enabled the visualization of the targeted accumulation and sustained recycling of Env between endocytic compartments (EC) and the VS. We observed dynamic exchange of Env at the VS, while the viral structural protein, Gag, was largely immobile at the VS. The disparate exchange rates of Gag and Env at the synapse support that the trafficking and/or retention of a majority of Env towards the VS is not maintained by entrapment by a Gag lattice or immobilization by binding to CD4 on the target cell. A FRAP study of an Env endocytosis mutant showed that recycling is not required for accumulation at the VS, but is required for the rapid exchange of Env at the VS. We conclude that the mechanism of Env accumulation at the VS and incorporation into nascent particles involves continuous internalization and targeted secretion rather than irreversible interactions with the budding virus, but that this recycling is largely dispensable for VS formation and viral transfer across the VS.

Single Cell Center of Mass for the Analysis of BMP Receptor Heterodimers Distributions

At the plasma membrane, transmembrane receptors are at the interface between cells and their environment. They allow sensing and transduction of chemical and mechanical extracellular signals. The spatial distribution of receptors and the specific recruitment of receptor subunits to the cell membrane is crucial for the regulation of signaling and cell behavior. However, it is challenging to define what regulates such spatial patterns for receptor localization, as cell shapes are extremely diverse when cells are maintained in standard culture conditions. Bone morphogenetic protein receptors (BMPRs) are serine-threonine kinases, which build heteromeric complexes of BMPRI and II. These are especially interesting targets for receptor distribution studies, since the signaling pathways triggered by BMPR-complexes depends on their dimerization mode. They might exist as preformed complexes, or assemble upon binding of BMP, triggering cell signaling which leads to differentiation or migration. In this work we analyzed BMPR receptor distributions in single cells grown on micropatterns, which allow not only to control cell shape, but also the distribution of intracellular organelles and protein assemblies. We developed a script called ComRed (Center Of Mass Receptor Distribution), which uses center of mass calculations to analyze the shift and spread of receptor distributions according to the different cell shapes. ComRed was tested by simulating changes in experimental data showing that shift and spread of distributions can be reliably detected. Our ComRed-based analysis of BMPR-complexes indicates that receptor distribution depends on cell polarization. The absence of a coordinated internalization after addition of BMP suggests that a rapid and continual recycling of BMPRs might occur. Receptor complexes formation and localization in cells induced by BMP might yield insights into the local regulation of different signaling pathways.

Photonic and Magnetic Dual-Responsive Molecularly Imprinted Sensor for Highly Specific Recognition of Enterovirus 71.

The specific identification and detection of a virus are the critical factors to identify and control an epidemic situation. In this study, a novel photonic-magnetic responsive virus-molecularly imprinted photochemical sensor was constructed for recognition of enterovirus 71. As designed, the double-bond-modified magnetic metal organic framework and 4-(4'-acryloyloxyazo) benzoic acid were used as a magnetic carrier and light-responsive functional monomer, respectively. The structure of the recognition site of the virus-molecularly imprinted nanospheres can be photo-switched between two different structures to achieve rapid release and specific binding to the target virus. Additionally, the introduction of a magnetic core enables a rapid separation and recycling of imprinted particles. The device achieves a performance with high-specificity recognition (imprinting factor = 5.1) and an ultrahigh sensitivity with a detection limit of 9.5 × 10-3 U/mL (3.9 fM). Moreover, it has good reproducibility and can be stored for as long as 6 months. Thus, the approach used in this work opens a new avenue for the construction of multiresponsive virus sensors.

Cell trafficking and regulation of osteoblastogenesis by extracellular vesicle associated bone morphogenetic protein 2.

Extracellular vesicles (EVs) are characterized by complex cargo composition and carry a wide array of signalling cargo, including growth factors (GFs). Beyond surface‐associated GFs, it is unclear if EV intralumenal growth factors are biologically active. Here, bone morphogenetic protein‐2 (BMP2), loaded directly into the lumen of EVs designated engineered BMP2‐EVs (eBMP2‐EVs), was comprehensively characterized including its regulation of osteoblastogenesis. eBMP2‐EVs and non‐EV ‘free’ BMP2 were observed to similarly regulate osteoblastogenesis. Furthermore, cell trafficking experiments suggest rapid BMP2 recycling and its extracellular release as ‘free’ BMP2 and natural occurring BMP2‐EVs (nBMP2‐EVs), with both being osteogenic. Interestingly, BMP2 occurs on the EV surface of nBMP2‐EVs and is susceptible to proteolysis, inhibition by noggin and complete dissociation from nBMP2‐EVs over 3 days. Whereas, within the eBMP2‐EVs, BMP2 is protected from proteolysis, inhibition by noggin and is retained in EV lumen at 100% for the first 24 h and ∼80% after 10 days. Similar to ‘free’ BMP2, bioprinted eBMP2‐EV microenvironments induced osteogenesis in vitro and in vivo in spatial registration to the printed patterns. Taken together, BMP2 signalling involves dynamic BMP2 cell trafficking in and out of the cell involving EVs, with distinct differences between these nBMP2‐EVs and eBMP2‐EVs attributable to the BMP2 cargo location with EVs. Lastly, eBMP2‐EVs appear to deliver BMP2 directly into the cytoplasm, initiating BMP2 signalling within the cell, bypassing its cell surface receptors.

On the learning of addictive behavior: Sensation-seeking propensity predicts dopamine turnover in dorsal striatum

We asked if sensation-seeking is linked to premorbid personality characteristics in patients with addictive disorders, or the characteristics follow the sensation-seeking activity. We interpreted the former as a state associated with normal rates of dopamine synthesis, and the latter as a trait of individuals with abnormally high rates of synthesis. We previously determined dopaminergic receptor density in striatum, and we now tested the hypothesis that an elevated dopaminergic condition with increased extracellular dopamine and receptor density follows increased dopamine synthesis capacity in highly sensation-seeking individuals, as measured by positron emission tomography of 18 men with tracer fluorodopa (FDOPA). We detected a site in left caudate nucleus where the volume of distribution of FDOPA-derived metabolites correlated negatively with FDOPA metabolite turnover, consistent with decreased metabolite breakdown in highly sensation-seeking subjects. High rates of sensation-seeking attenuated the dopamine turnover in association with a low rate of dopamine recycling, low dopamine oxidation, and elevated extracellular dopamine and receptors in caudate nucleus. In contrast, low rates of sensation-seeking were associated with rapid dopamine recycling, rapid dopamine oxidation, low extracellular dopamine, and low receptor density. We conclude that the modulation of dopaminergic neurotransmission associated with sensation-seeking is a state of sensation-seeking, rather than a trait of personality following abnormal regulation of dopaminergic neurotransmission.

Numerical simulation of suction bucket foundation response located in liquefiable sand under earthquakes

The suction bucket foundation is considered as an effective option for offshore wind turbines because of its advantages in rapid installation and recyclability. However, the depth of the suction bucket inserted into the seabed is shallower compared to the monopile. Earthquakes and liquefaction threaten the safety and stability of suction bucket foundations in the North Sea of Europe and the Chinese offshore where earthquakes are active and the seabed is prone to liquefaction. This paper investigated the behavior of the suction bucket foundation located in the liquefiable sand under earthquakes using an advanced liquefaction model. The FE-FD method with the cyclic mobility constitutive model for soil was used to carry out the nonlinear dynamic analyses. Responses of the excess pore water pressure ratio, acceleration, displacement, and rotation were studied under different earthquake magnitudes and sand density. The distribution of excess pore water pressure of the suction bucket foundation from the results show strong space-time characteristics. The failure mechanism of the suction bucket foundation after liquefaction was revealed. The numerical results indicate that offshore wind turbines will be subjected to permanent displacements and tilt to reach 40% of the safety threshold due to earthquakes and liquefaction. Thus, seismic load and liquefaction of the foundation must be considered in the design.

Rapid recycling of subducted sedimentary carbon revealed by Afghanistan carbonatite volcano

Rapid recycling of subducted sedimentary carbon revealed by Afghanistan carbonatite volcano

Rapid endogenic rock recycling in magmatic arcs

In subduction zones, materials on Earth’s surface can be transported to the deep crust or mantle, but the exact mechanisms and the nature of the recycled materials are not fully understood. Here, we report a set of migmatites from western Yangtze Block, China. These migmatites have similar bulk compositions as forearc sediments. Zircon age distributions and Hf–O isotopes indicate that the precursors of the sediments were predominantly derived from juvenile arc crust itself. Using phase equilibria modeling, we show that the sediments experienced high temperature-to-pressure ratio metamorphism and were most likely transported to deep arc crust by intracrustal thrust faults. By dating the magmatic zircon cores and overgrowth rims, we find that the entire rock cycle, from arc magmatism, to weathering at the surface, then to burial and remelting in the deep crust, took place within ~10 Myr. Our findings highlight thrust faults as an efficient recycling channel in compressional arcs and endogenic recycling as an important mechanism driving internal redistribution and differentiation of arc crust.