Search

Tetrahydrofuran rings are present in a wide variety of biologically active molecules, which highlights the importance of developing a mild, convenient method for synthesizing compounds bearing these rings. Herein, we report an electrochemical protocol for phosphorous acid-assisted synthesis of hemiaminal ethers by means of α-C(sp³)-H/N-H cross-coupling reactions between tetrahydrofuran and sulfonamides or amides. This protocol does not require a chemical oxidant and can be performed at room temperature. Various sulfonamides and amides were suitable substrates, giving moderate to high yields of the desired cross-coupling products. [ABSTRACT FROM AUTHOR]

Continuous risky decisions refer to decisions that involve trade-offs among options with persistent risks. People can use the probability of occurrence per unit time (e.g., 'the probability of occurrence is 1% per month') or the average time of risk occurrence (e.g., 'the average occurrence time is 100 months') to represent continuous risky options. In this study, we examined the effect of the presentation format (i.e., the probability of occurrence per unit time vs. the average time of risk occurrence) on continuous risky decisions in the gain domain and further explored the underlying mechanism. In Study 1 (N = 122), we demonstrated the effect of presentation format on continuous risky decisions and the moderating effect of the magnitude of probabilities. Specifically, when the probabilities were relatively low, compared with the probability of occurrence per unit time, using the average time of risk occurrence to present the continuous risky options led to more risk-averse decisions. However, when the probabilities were relatively high, compared with the probability of occurrence per unit time, the presentation format of the average time occurrence led to more risk-seeking decisions. In Study 2 (N = 136), we found that the moderating effect of the option probabilities on continuous risky decisions wasmediated by the subjective attributewise difference judgment. In Study 3 (N = 221), we replicated the effect of presentation format on continuous risky decisions in more natural scenarios. The study offered a deep understanding of the mechanism of continuous risky decision-making, and the results were conducive to further developing theories in relevant fields. [ABSTRACT FROM AUTHOR]

Using first-principles calculations, we show that Mn and Cr layers under graphene exhibit almost zero magnetic moment due to anti-ferromagnetic order, while ferromagnetic coupling in Fe, Co, and Ni leads to large magnetic moment. Transition metal partially supported graphene, with a mixture of supported and pristine areas, exhibits an oscillatory electrostatic potential, thus alternating the electric field across the supported and pristine areas. Such an effect can be utilized to control mass transport and nanostructure self-organization on graphene at the atomic level. [ABSTRACT FROM AUTHOR]

The bacteria LPS is one of the leading endotoxins responsible for sepsis; its sensing pathway-induced pyroptosis plays an important role in innate immunity. However, excessive pyroptosis might cause immunological diseases, even multiple organ failure and death by undefined mechanisms. Given that the development of acute kidney injury (AKI) in patients with sepsis causes significant morbidity and mortality, the mechanism of pyroptosis in regulating septic AKI remains unknown. In this study, we establish a zebrafish crispant in vivo analysis model and reveal that both caspy2 and gasdermin Eb (GSDMEb) contribute to lethal LPS-induced septic shock. Meanwhile, the in vitro analysis reveals that caspy2 activation can specifically cleave GSDMEb to release its N terminus to mediate pyroptosis, which functions as GSDMD in mammals. Interestingly, we establish an in vivo propidium iodide-staining method and reveal that the caspy2-GSDMEb signaling cascade is essential for enhancing renal tubular damage during lethal LPS-induced septic shock, whereas administration of the zebrafish-specific GSDMEb-derived peptide inhibitor Ac-FEID-CMK can attenuate mortality and septic AKI in vivo. Moreover, we confirm that either caspase-11 or GSDMD deficiency decreases both inflammatory cytokines and kidney dysfunction enzyme release and prolongs survival in a murine model of septic shock. Taken together, these findings demonstrate an evolutionary executor for pyroptosis in zebrafish and reveal that the pyroptosis of renal tubular cells is a major cause of septic AKI, and also provide an ideal in vivo screening model for potential antisepsis therapeutic strategies. [ABSTRACT FROM AUTHOR]

The study of pollution due to combined antibiotics and metals is urgently needed. Photochemical processes are an important transformation pathway for antibiotics in the environment. The mechanisms underlying the effects of metal-ion complexation on the aquatic photochemical transformation of antibiotics in different dissociation forms are crucial problems in science, and beg solutions. Herein, we investigated the mechanisms of direct photolysis of norfloxacin (NOR) in different dissociation forms in water and metal ion Mg2+ effects using quantum chemical calculations. Results show that different dissociation forms of NOR had different maximum electronic absorbance wavelengths (NOR2+ < NOR0 < NOR+) and showed different photolysis reactivity. Analysis of transition states (TS) and reaction activation energies (Ea) indicated NOR+ generally underwent loss of the piperazine ring (C10-N13 bond cleavage) and damage to piperazine ring (N13-C14 bond cleavage). For NOR2+, the main direct photolysis pathways were de-ethylation (N7-C8 bond cleavage) and decarboxylation (C2-C5 bond cleavage). Furthermore, the presence of Mg2+ changed the order of the wavelength at maximum electronic absorbance (NOR+-Mg2+ < NOR0-Mg2+ < NOR2+-Mg2+) and increased the intensities of absorbance peaks of all three dissociation species of NOR, implying that Mg2+ played an important role in the direct photolysis of NOR0, NOR+, and NOR2+. The calculated TS results indicated that the presence of Mg2+ increased Ea for most direct photolysis pathways of NOR, while it decreased Ea for some direct photolysis pathways such as the loss of the piperazine ring and the damage of the piperazine ring of NOR0 and the defluorination of NOR+. [ABSTRACT FROM AUTHOR]

Microwave over-the-horizon (OTH) propagation through troposcatter is a valuable candidate for remote targets detection. Array antenna is promising to handle the contradiction between real-time wide spatial coverage requirement and high antenna gain to capture weak scattering signal. The detection tactics and performance of array receiving systems are significantly affected by the fading correlation between array antennas, but there is no analytical study which considers the fading correlation in troposcatter passive sensing environments for uncooperative targets. In this study, an analytical method based on a scattering transfer function is proposed to derive the channel fading correlation, and the result is a function of transmitter deviation and spatial, temporal, frequency, angular separations of receiving array antennas in uncooperative troposcatter circumstances. In addition, the OTH troposcatter array receiving signal model is derived by exploiting the fading correlation to form the covariance structure of the received array signal, adding up with the signal transmission loss. Existing experimental results validate the derived fading correlations, and the simulation results validate the OTH passive detection performance based on the provided signal model. [ABSTRACT FROM AUTHOR]

The finite volume and volume of fluid (VOF) methods are used to simulate the two-dimensional nonlinear parametric sloshes in the U-shaped and the circular tanks. An experiment is simultaneously conducted to observe and measure the responses of two-dimensional nonlinear parametric sloshes. The natural frequencies and the nonlinear steady-state amplitude-frequency responses are respectively acquired and compared by numerical and experimental methods. The numerical results have a good agreement with the experimental values. Because the viscous damping is automatically considered in the numerical simulations, the steady-state wave amplitudes of parametric resonance (sloshing) are well predicted. The finite volume and VOF techniques aided by Fluent Code can be a practical tool for the engineers to analyze the long-time nonlinear parametric sloshing in arbitrary-shape tanks. [ABSTRACT FROM AUTHOR]

The beyond-line-of-sight (BLOS) ranging of radiation sources can be realised through the troposcatter propagation of electromagnetic signals. Present troposcatter ranging systems are based on multi-station cross localisation theory wherein synchronisation and data fusion of all stations are not tractable. The troposcatter signal group delay properties provide a new ranging mechanism that can be realised through a single station conveniently and inexpensively. However, for radiation sources with multibeams, e.g. frequency-scanned radar, which forms several sub-beams with different elevation angles in the vertical direction, the scattering signal of sub-beams with high elevation angles has overall hysteresis compared to lower ones. This effect is called group delay between sub-beams. In this study, a one-to-one correspondence between group delay and target distance is derived to a closed-form expression with target and receiver antenna parameters. Furthermore, a group-delay-based passive ranging mechanism is proposed for exploiting this correspondence to increase the range of the BLOS target. Then two indicators for evaluation, ranging resolution and delay-measure requirement, are proposed for investigating ranging performance under the receiving antenna mode with different elevation angles, vertical beamwidths and erection heights. Results show the ranging resolution is ∼0.1-0.3 μs/300 km and delay-measure requirement is ∼0.002-0.033 μs for the given parameters. [ABSTRACT FROM AUTHOR]

The detection of existence of fullerenes (C60 and C70) makes it necessary to explore whether soot nanoparticles can participate in new nanometer-sized particle formation and growth in the atmosphere. This study describes a theoretical investigation at multiple levels on the role of the fullerenes (as model compounds to represent nanoparticles of soot) in the formation of complexes with a common atmospheric nucleating precursor (sulfuric acid, SA) and a biogenic organic acid (cis-pinonic acid, CPA), as well as initial growth of nano-sized biogenic aerosols. Quantum chemical density-functional theory calculations identify the formation of stable fullerene-[CPA-SA] ternary complexes, which likely leads to an enhanced nucleation of SA with CPA. Relevant thermochemical parameters including the changes of Gibbs free energy, enthalpy, and entropy for the complex formation also support that fullerene-[CPA-SA] is most likely to be a newly formed nuclei. The sizes of the critical nucleus of the fullerene-[CPA-SA-H2O] systems were found to be approximately 1.3 nm by large-scale molecular dynamics simulations. This study may provide a new insight into the mechanisms underlying the formation of new particle in the atmospheric environment. [ABSTRACT FROM AUTHOR]

Interaction between K adatoms on graphene is investigated by first-principles calculations based on density function theory and analytical analyses based on the k ' p perturbation theory. The calculation shows that there is a strong repulsion between K adatoms. The main origin of this strong repulsion is not from the dipole-dipole interaction as suggested for K adatoms on graphite surface, but comes from the screened Coulomb interaction. Potassium adatom on graphene donates its s electron and becomes K+. The positively charged K adatom induces electron density oscillation on graphene which is responsible for the screened Coulomb repulsion between the K adatoms. [ABSTRACT FROM AUTHOR]

Adsorption of Fe atom and Fen (n = 2-7) clusters on graphene was studied by first-principles calculation and chemical bonding analysis. Various adsorption configurations, i.e., Fe clusters placed at different lateral positions and with different orientations with respect to the graphene lattice, have been optimized to locate the ground-state geometry of the Fe clusters on graphene. The calculation shows that Fe on graphene prefers a three-dimensional growth mode with a critical size of two atoms. The calculation also shows that Fen clusters on graphene exhibit ferromagnetic order and large magnetic moment. However, due to charge redistribution caused by the interaction with graphene, some Fen clusters on graphene have smaller magnetic moments compared to the corresponding free-standing clusters. Adsorption of Fen clusters also induces magnetic moments in graphene, and the induced magnetic moment on each carbon atom in graphene is correlated with the distortion of the graphene lattice. [ABSTRACT FROM AUTHOR]

Mechanisms underlying the impacts of interactions between carbon nanoparticles (CNPs) and ionic liquids (ILs) on the physicochemical behavior of CNPs need to be more full worked out. This manuscript describes a theoretical investigation at multiple levels on the interactions of fullerene C60 with 21 imidazolium-based ILs of varying alkyl side chain lengths and anionic types and their impacts on C60 dispersion behavior. Results show that π-cation interaction contributed to mechanism of the C60-IL interaction more than π-anion interaction. The calculated interaction energy (EINT) indicates that C60 can form stable complex with each IL molecule. Moreover, the direction of charge transfer occurred from IL to C60 during the C60-IL interaction. Quantitative models were developed to evaluate the self-diffusion coefficient of C60 (Dfullerene) in bulk ILs. Three interpretative molecular descriptors (heat of formation, EINT, and charge) that describe the C60-IL interactions and the alkyl side chain length were found to be determinants affecting Dfullerene. [ABSTRACT FROM AUTHOR]

When the thickness of ultrathin metal films approaches the nanometer scale comparable to the coherence length of the electrons, significant effects on the structure stability and the electronic properties of the metal films emerge due to electron confinement and quantization of the allowed electronic states in the direction perpendicular to the film. Using first-principles calculations, we showed that such quantum size effects can induce oscillatory electrostatic potential and thus alternating electric field on the surface of the wedge-shaped Pb(111) films. The alternating electric field has significant influence on surface reactivity, leading to selective even- or odd-layer adsorption preference depending on the charge state of the adatoms, consistent with the odd-layer preference of higher Mg coverage on wedge-shaped Pb(111) films, as observed in experiment. [ABSTRACT FROM AUTHOR]

An approximate analytical solution of sloshing frequencies for a liquid in the various shape aqueducts is formulated by using the Ritz method. The present approximate method is, respectively, applied to find the sloshing frequencies of the liquid in rectangular, trapezoid, oval, circular, U-shaped tanks (aqueducts), and various shape tuned liquid dampers (TLD). The first three antisymmetric and symmetric frequencies by the present approach are within 5% accuracy compared to the other analytical, numerical, and experimental values. The approximate solutions of this paper for the various shape aqueducts are acceptable to the engineering applications. [ABSTRACT FROM AUTHOR]

Online algorithms that process one example at a time are advantageous when dealing with very large data or with data streams. Stochastic Gradient Descent (SGD) is such an algorithm and it is an attractive choice for online Support Vector Machine (SVM) training due to its simplicity and effectiveness. When equipped with kernel functions, similarly to other SVM learning algorithms, SGD is susceptible to the curse of kernelization that causes unbounded linear growth in model size and update time with data size. This may render SGD inapplicable to large data sets. We address this issue by presenting a class of Budgeted SGD (BSGD) algorithms for large-scale kernel SVM training which have constant space and constant time complexity per update. Specifically, BSGD keeps the number of support vectors bounded during training through several budget maintenance strategies. We treat the budget maintenance as a source of the gradient error, and show that the gap between the BSGD and the optimal SVM solutions depends on the model degradation due to budget maintenance. To minimize the gap, we study greedy budget maintenance methods based on removal, projection, and merging of support vectors. We propose budgeted versions of several popular online SVM algorithms that belong to the SGD family. We further derive BSGD algorithms for multi-class SVM training. Comprehensive empirical results show that BSGD achieves higher accuracy than the state-of-the-art budgeted online algorithms and comparable to non-budget algorithms, while achieving impressive computational efficiency both in time and space during training and prediction. [ABSTRACT FROM AUTHOR]

The multiple instance regression (MIR) problem arises when a data set is a collection of bags, where each bag contains multiple instances sharing the identical real-valued label. The goal is to train a regression model that can accurately predict label of an unlabeled bag. Many remote sensing applications can be studied within this setting. We propose a novel probabilistic framework for MIR that represents bag labels with a mixture model. It is based on an assumption that each bag contains a prime instance which is responsible for the bag label. An expectation-maximization algorithm is proposed to maximize the likelihood of the mixture model. The mixture model MIR framework is quite flexible, and several existing MIR algorithms can be described as its special cases. The proposed algorithms were evaluated on synthetic data and remote sensing data for aerosol retrieval and crop yield prediction. The results show that the proposed MIR algorithms achieve higher accuracy than the previous state of the art. [ABSTRACT FROM AUTHOR]

We investigate vibrational properties and lattice distortion of negatively charged nitrogen-vacancy (NV-) center in diamond. Using the first-principles electronic structure calculations, we show that the presence of NV- center leads to appearance of a large number of quasilocalized vibrational modes (qLVMs) with different degrees of localization. The vibration patterns and the symmetries of the qLVMs are presented and analyzed in detail for both ground and excited orbital states of the NV- center. We find that in the high-symmetry (C3v) excited orbital state a pair of degenerate qLVMs becomes unstable, i.e., has formally negative frequencies, and the stable excited state has lower (C1h) symmetry. This is a direct indication of the Jahn-Teller effect, and our studies suggest that the dynamical Jahn-Teller effect in the weak-coupling regime takes place. We have also performed a detailed comparison of our results with the available experimental data on the vibrations involved in optical emission/absorption of the NV- centers. We have directly demonstrated that, among other modes, the qLVMs crucially impact the optical properties of the NV- centers in diamond, and identified the most important groups of qLVMs. Our results are important for deeper understanding of the optical properties and the orbital relaxation associated with lattice vibrations of the NV- centers. [ABSTRACT FROM AUTHOR]

Dual-specificity phosphatase 12 (DUSP12) is abnormally expressed under various pathological conditions and plays a crucial role in the pathological progression of disorders. however, the role of DUSP12 in cerebral ischaemia/reperfusion injury has not yet been investigated. this study explored the possible link between DUSP12 and cerebral ischaemia/reperfusion injury using an oxygen-glucose deprivation/ reoxygenation (OGD/R) model. Marked decreases in DUSP12 levels have been observed in cultured neurons exposed to OGD/R. DUSP12-overexpressed neurons were resistant to OGD/R-induced apoptosis and inflammation, whereas DUSP12-deficient neurons were vulnerable to OGD/R-evoked injuries. Further investigation revealed that DUSP12 overexpression or deficiency affects the phosphorylation of apoptosis signal-regulating kinase 1 (ASK1), c-Jun NH2-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) in neurons under OGD/R conditions. Moreover, blockade of ASK1 diminished the regulatory effect of DUSP12 deficiency on JNK and p38 MAPK activation. in addition, DUsP12-deficiency-elicited effects exacerbating neuronal OGD/R injury were reversed by ASK1 blockade. in summary, DUSP12 protects against neuronal OGD/R injury by reducing apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway. these findings imply a neuroprotective function for DUSP12 in cerebral ischaemia/reperfusion injury. [ABSTRACT FROM AUTHOR]

In diamond and zinc blende crystals, the competition between glide and shuffle-set slips has been intensively studied. In particular, the undissociated screw dislocation in Si seen at low temperature about five years ago was generally believed to be shuffle set. In this letter, the authors have performed tight-binding and density functional theory calculations that show that a glide-set C core has lower energy than the shuffle-set A core after period-doubling reconstruction. Since the C core can cross slip between two glide-set planes, it satisfies all the experimental observations to date, and may play important roles in dislocation cross slip and ductile-to-brittle transition in these materials. [ABSTRACT FROM AUTHOR]

Troposcatter propagation mechanism is valuable for beyond-line-of-sight surveillance. However, channel fading caused by multipath scattering limits the sensing performance of the existing equipment. Based on the troposcatter multipath channel fading model on frequency and spatial domain, a modified covariance-based detector is proposed. The captured array signals are first maximal ratio combined in frequency domain and then weighted in spatial domain before accumulation. The performance of the proposed detector is derived theoretically and verified through simulations, showing significant improvement in the troposcatter scenario. [ABSTRACT FROM AUTHOR]

Ammonium nickel phosphate has a large specific capacitance as an electrode material at low current density, but its capacitance decays fast at high current density, which directly affects the rate performance of supercapacitors. Herein, we demonstrate a facile route for the controllable synthesis of hierarchical self-assembly flower-like ammonium nickel phosphate as a high-rate electrode material for asymmetric supercapacitors, which is an important strategy to enhance the energy density at high power density. The flower-like structures are hierarchically assembled by a mass of rectangular sheets, which can provide fast electron transport and short ion diffusion path, thereby exhibiting excellent electrochemical performance with ultrahigh specific capacitance of 1016 F g−1 at 1.0 A g−1. More importantly, the NH4NiPO4 · H2O materials exhibit outstanding rate performance (800 F g−1 even at large current density of 30 A g−1) and superior long-term cycle life (83% of capacity retention up to 3000 cycles at 5 A g−1). Furthermore, the NH4NiPO4 · H2O//AC asymmetric supercapacitors are assembled in aqueous KOH electrolyte, and exhibit high energy density (46.2 Wh kg−1 at 160 W kg−1 and 26.7 Wh kg−1 at a large power density of 4000 W kg−1, respectively). Due to the outstanding electrochemical performance, the all-solid-state asymmetric supercapacitors are successfully constructed using these materials. [ABSTRACT FROM AUTHOR]

The concerns about the supply and resource of rare earth (RE) metals have generated a lot of interests in searching for high performance RE-free permanent magnets. Alnico alloys are traditional non-RE permanent magnets and have received much attention recently due their good performance at high temperature. In this paper, we develop an accurate and efficient cluster expansion energy model for alnico 5-7. Monte Carlo simulations using the cluster expansion method are performed to investigate the structure of alnico 5-7 at atomistic and nano scales. The alnico 5-7 master alloy is found to decompose into FeCo-rich and NiAl-rich phases at low temperature. The boundary between these two phases is quite sharp (∼2 nm) for a wide range of temperature. The compositions of the main constituents in these two phases become higher when the temperature gets lower. Both FeCo-rich and NiAl-rich phases are in B2 ordering with Fe and Al on α-site and Ni and Co on -site. The degree of order of the NiAl-rich phase is much higher than that of the FeCo-rich phase. A small magnetic moment is also observed in NiAl-rich phase but the moment reduces as the temperature is lowered, implying that the magnetic properties of alnico 5-7 could be improved by lowering annealing temperature to diminish the magnetism in NiAl-rich phase. The results from our Monte Carlo simulations are consistent with available experimental results. [ABSTRACT FROM AUTHOR]

Ni is the second most abundant element in the Earth's core. Yet, its effects on the inner core's structure and formation process are usually disregarded because of its electronic and size similarity with Fe. Using ab initio molecular dynamics simulations, we find that the bcc phase can spontaneously crystallize in liquid Ni at temperatures above Fe's melting point at inner core pressures. The melting temperature of Ni is shown to be 700 to 800 K higher than that of Fe at 323 to 360 GPa. hcp, bcc, and liquid phase relations differ for Fe and Ni. Ni can be a bcc stabilizer for Fe at high temperatures and inner core pressures. A small amount of Ni can accelerate Fe's crystallization at core pressures. These results suggest that Ni may substantially impact the structure and formation process of the solid inner core. [ABSTRACT FROM AUTHOR]

Intriguing topological phases may appear in both insulating and semimetallic states. Topological insulators exhibit topologically nontrivial band inversion, while topological Dirac/Weyl semimetals show "relativistic" linear band crossings. Here, we report an unusual topological state of Pt3Sn, where the two topological features appear simultaneously. Based on first-principles calculations, we show that Pt3Sn is a three-dimensional weak topological semimetal with topologically nontrivial band inversion between the valence and conduction bands, where the band structure also possesses type-II Dirac points at the boundary of two electron pockets. The formation of the Dirac points can be understood in terms of the representations of relevant symmetry groups and the compatibility relations. The topological surface states appear in accordance with the nontrivial bulk band topology. The unique coexistence of the two distinct topological features in Pt3Sn enlarges the material scope in topological physics, and is potentially useful for spintronics. [ABSTRACT FROM AUTHOR]

In this paper, a kind of gas support generated by the magnetic fluids seal is investigated numerically and experimentally. Theoretical analysis and experimental tests both indicate that the load carrying capacity of the bearing is mainly determined by the sealing capacity of the magnetic fluids. The experiments also reveal that the load capacity may change with the volumes of magnetic fluids and the air sealed by magnetic fluids. [ABSTRACT FROM AUTHOR]

Although unstable, the Si(337) orientation has been known to appear in diverse experimental situations such as the nanoscale faceting of Si(112), or in the case of miscutting a Si(113) surface. Various models for Si(337) have been proposed over time, which motivates a comprehensive study of the structure of this orientation. Such a study is undertaken in this article, where we report the results of a genetic algorithm optimization of the Si(337)-(2×1) surface. The algorithm is coupled with a highly optimized empirical potential for silicon, which is used as an efficient way to build a set of possible Si(337) models; these structures are subsequently relaxed at the level of ab initio density-functional methods. Using this procedure, we retrieve the (337) reconstructions proposed in previous works, as well as a number of different ones. [ABSTRACT FROM AUTHOR]

Objective: Hypertension is one of the leading causes of human death and disability. MTHFR and MTRR regulate folate metabolism and are closely linked to hypertension, although the relationship is inconsistent among different ethnic groups. The present study aims to investigate the effects of MTHFR C677T (rs1801133), MTHFR A1298C (rs1801131), and MTRR A66G (rs1801394) polymorphisms on hypertension susceptibility in the Bai nationality of the Yunnan Province, China. Methods: This case-control study included 373 hypertensive patients and 240 healthy controls from the Chinese Bai population. The genotyping of MTHFR and MTRR gene polymorphisms was carried out by using the KASP method. The effects of genetic variations of MTHFR and MTRR genes on hypertension risk were evaluated with odds ratios (OR) and 95% confidence intervals (95% CI). Results: The present study revealed that the CT and TT genotypes and T allele of MTHFR C677T locus were considerably associated with an increased risk of hypertension. In addition, MTHFR A1298C locus CC genotype could significantly increase the hypertension risk. The T-A and C-C haplotypes of MTHFR C677T and MTHFR A1298C could increase the risk of hypertension. Further stratified analysis by risk rank of folate metabolism indicated that people with poor utilization of folic acid were more prone to develop hypertension. In the hypertension group, the MTHFR C677T polymorphism was significantly associated with fasting blood glucose, fructosamine, apolipoprotein A1, homocysteine, superoxide dismutase, and malondialdehyde levels. Conclusion: Our study suggested that genetic variations of MTHFR C677T and MTHFR A1298C were significantly associated with susceptibility to hypertension in the Bai population from Yunnan, China. [ABSTRACT FROM AUTHOR]

Structures and magnetic properties of Fe16−xCoxN2 are studied using adaptive genetic algorithm and first-principles calculations. We show that substituting Fe with Co in Fe16N2 with a Co/Fe ratio ≤1 can greatly improve the magnetic anisotropy of the material. The magnetocrystalline anisotropy energy from first-principles calculations reaches 3.18MJ/m³ (245.6 μeV per metal atom) for Fe12Co4N2, much larger than that of Fe16N2, and is one of the largest among the reported rare-earth-free magnets. From our systematic crystal structure searches, we show that there is a structure transition from tetragonal Fe16N2 to cubic Co16N2 in Fe16−xCoxN2 as the Co concentration increases, which can be well explained by electron counting analysis. Different magnetic properties between the Fe-rich (x ≤ 8) and Co-rich (x>8) Fe16−xCoxN2 is closely related to the structural transition. [ABSTRACT FROM AUTHOR]

This paper reports on a new secondary instability phenomenon of parametric sloshing. Faraday first experimentally discovered the (1/2 sub-harmonic) parametric sloshing phenomenon in 1831. The parametric instability starts from a small disturbance on the free fluid surface, and then the sloshing amplitude of fluid increases exponentially and finally reaches a steady-state limit cycle oscillation. This parametric instability is called the first (linear) instability. The parametric sloshing experiment of this study discovers that in the case of the parametric excitation unchanged, the free fluid surface that is in a limit cycle oscillation might undergo a secondary instability. Under this circumstance, the sloshing amplitude of free surface increases sharply. The consequence is catastrophic - the fluid is splashed out of the tank. During the secondary instability, the sloshing mode (or energy) is transferred from the third mode to the first mode. The secondary instability, which is different from the first instability, is a nonlinear unstable process. The mechanism of the secondary instability is needed a further study. [ABSTRACT FROM AUTHOR]

Magnetic materials are essential for energy generation and information devices, and they play an important role in advanced technologies and green energy economies. Currently, the most widely used magnets contain rare earth (RE) elements. An outstanding challenge of notable scientific interest is the discovery and synthesis of novel magnetic materials without RE elements that meet the performance and cost goals for advanced electromagnetic devices. Here, we report our discovery and synthesis of an RE-free magnetic compound, Fe3CoB2, through an efficient feedback framework by integrating machine learning (ML), an adaptive genetic algorithm, first-principles calculations, and experimental synthesis. Magnetic measurements show that Fe3CoB2 exhibits a high magnetic anisotropy (K1 = 1.2 MJ/m³ ) and saturation magnetic polarization (Js = 1.39 T), which is suitable for RE-free permanent-magnet applications. Our ML-guided approach presents a promising paradigm for efficient materials design and discovery and can also be applied to the search for other functional materials. [ABSTRACT FROM AUTHOR]

Paraffin melting is widely applied to the fields of PCM energy storage, gathering and transportation pipe-line paraffin removal, etc. Natural-convection is the main heat transfer mode during paraffin melting, and Rayleigh number is an important factor affecting the change of natural-convection intensity. Nusselt number variation can reflect the influence of natural-convection on heat transfer. The conventional Nusselt number of hot wall surface reflects only the convective heat transfer intensity of the fixed wall, while it does not take into account that the phase change interface has the characteristics of moving in the phase change process. A double distribution model of paraffin phase transformation in circular tube based on lattice Boltzmann method is established in this paper. The influence of Rayleigh number on the temperature field and flow field of wax in circular tube is analyzed. The heat transfer process is reflected by Nusselt number of moving phase interface. The relation between Nusselt number of moving interface and Nusselt number of hot wall surface is also presented. The results show that the Nusselt number of moving phase interface can reflect the complex non-linear characteristics of natural- convection and describe the phase change heat transfer process of wax more accurately. Calculation formula of Nusselt number of moving phase interface and hot wall during wax phase change is proposed. Increasing Rayleigh number can quicken the melting of wax to meet the actual engineering requirements. [ABSTRACT FROM AUTHOR]

Hyperbaric oxygen (HBO) is widely used in military operations, especially underwater missions. However, prolonged and continuous inhalation of HBO can cause central nervous system oxygen toxicity (CNS-OT), which greatly limits HBO׳s application. The regulation of astrocytes to the metabolism of adenosine is involved in epilepsy. In our study, we aimed to observe the effects of HBO exposure on the metabolism of adenosine in the brain. Furthermore, we aimed to confirm the possible mechanism underlying adenosine׳s mediation of the CNS-OT. Firstly, anesthetized rats exposed to 5 atm absolute HBO for 80 min. The concentrations of extracellular adenosine, ATP, ADP, and AMP were detected. Secondly, free-moving rats were exposed to HBO at the same pressure for 20 min, and the activities of 5’-nucleotidase and ADK in brain tissues were measured. For the mechanism studies, we observed the effects of a series of different doses of drugs related to adenosine metabolism on the latency of CNS-OT. Results showed HBO exposure could increase adenosine content by inhibiting ADK activity and improving 5′-nucleotidase activity. And adenosine metabolism during HBO exposure may be a protective response against HBO-induced CNS-OT. Moreover, the improvement of adenosine concentration, activation of adenosine A 1 R, or suppression of ADK and adenosine A 2A R, which are involved in the prevention of HBO-induced CNS-OT. This is the first study to demonstrate HBO exposure regulated adenosine metabolism in the brain. Adenosine metabolism and adenosine receptors are related to HBO-induced CNS-OT development. These results will provide new potential targets for the termination or the attenuation of CNS-OT. [ABSTRACT FROM AUTHOR]

We perform first-principles calculations of elemental cerium and compute its pressure-temperature phase diagram, finding good quantitative agreement with the experiments. Our calculations indicate that, while a signature of the volume-collapse transition appears in the free energy already at low temperatures, at higher temperatures this signature is enhanced because of the entropic effects, and originates an actual thermodynamical instability. Furthermore, we find that the catalyst determining this feature is-in all temperature regimes-a pressure-induced effective reduction of the f-level degeneracy due to the spin-orbit coupling. Our analysis suggests also that the lattice vibrations might be crucial in order to capture the behavior of the pressure-temperature transition line at large temperatures. [ABSTRACT FROM AUTHOR]

Group-14 elements, including C, Si, Ge, and Sn, can form various stable and metastable structures. Finding new metastable structures of group-14 elements with desirable physical properties for new technological applications has attracted a lot of interest. Using a genetic algorithm, we discovered a new low-energy metastable distorted sp3- hybridized framework structure of the group-14 elements. It has P42/mnm symmetry with 12 atoms per unit cell. The void volume of this structure is as large as 139.7 Å3 for Si P42/mnm, and it can be used for gas or metal-atom encapsulation. Band-structure calculations show that P42/mnm structures of Si and Ge are semiconducting with energy band gaps close to the optimal values for optoelectronic or photovoltaic applications. With metal-atom encapsulation, the P42/mnm structure would also be a candidate for rattling-mediated superconducting or used as thermoelectric materials. [ABSTRACT FROM AUTHOR]

We present zero-temperature first-principles calculations of elemental cerium and we compute its pressure-volume phase diagram within a theoretical framework able to describe simultaneously both the a and the γ phases. A surprising result revealed by our study is the presence of a clear signature of the transition at zero temperature and that this signature can be observed if and only if the spin-orbit coupling is taken into account. Our calculations indicate that the transition line in the pressure-temperature phase diagram of this material has a low-T critical point at negative pressures, placed very close to zero temperature. This suggests that cerium is very close to being "quantum critical," in agreement with recent experiments. [ABSTRACT FROM AUTHOR]

We propose three phases of H20 under ultrahigh pressure. Our structural search was performed using an adaptive genetic algorithm which allows an extensive exploration of crystal structure at density functional theory accuracy. The sequence of pressure-induced transitions beyond ice X at 0 K should be ice X → Pbcm → Pbca → Pmc21 → P21 → P21/c phases. Across the Pmc21-P21 transition, the coordination number of oxygen increases from 4 to 5 with a significant increase of density. All stable crystalline phases have nonmetallic band structures up to 7 TPa. [ABSTRACT FROM AUTHOR]

The atomic structure of Al90Sm10 metallic glass is studied using molecular dynamics simulations. By performing a long sub-Tg annealing, we developed a glass model closer to the experiments than the models prepared by continuous cooling. Using the cluster alignment method, we found that "3661" cluster is the dominating short-range order in the glass samples. The connection and arrangement of "3661" clusters, which define the medium-range order in the system, are enhanced significantly in the sub-Tg annealed sample as compared with the fast cooled glass samples. Unlike some strong binary glass formers such as Cu64.5Zr35.5, the clusters representing the short-range order do not form an interconnected interpenetrating network in Al90Sm10, which has only marginal glass formability. [ABSTRACT FROM AUTHOR]

The structures and magnetic properties of Co-Zr-B alloys near the composition of Co5Zr with B at. % ≤6% were studied using adaptive genetic algorithm and first-principles calculations. The energy and magnetic moment contour maps as a function of chemical composition were constructed for the Co-Zr-B magnet alloys through extensive structure searches and calculations. We found that Co-Zr-B system exhibits the same structure motif as the "Co11Zr2" polymorphs, and such motif plays a key role in achieving strong magnetic anisotropy. Boron atoms were found to be able to substitute cobalt atoms or occupy the "interruption" sites. First-principles calculations showed that the magnetocrystalline anisotropy energies of the boron-doped alloys are close to that of the high-temperature rhombohedral Co5Zr phase and larger than that of the low-temperature Co5.25Zr phase. Our calculations provide useful guidelines for further experimental optimization of the magnetic performances of these alloys. [ABSTRACT FROM AUTHOR]

The formation of neutrophil extracellular trap (NET) is a critical host defense when neutrophils migrate to infection sites. Pyroptosis is a newly identified programmed cell death, which is tightly regulated by inflammasome activation. However, the mechanism of pyroptotic signaling participating in NET production remains to be elucidated. In this study, the zebrafish larvae otic vesicle microinjection model was used to infect larvae with hemolysin-overexpressing Edwardsiella piscicida (EthA+), and a rapid migration of neutrophils to infection sites was observed. Intriguingly, EthA+ infection effectively induced significant neutrophil membrane rupture in vivo, which was dependent on caspase-B (caspy2) and gasdermin Eb (GSDMEb) but not caspase-A or gasdermin Ea. Specifically, the EthA+ E. piscicida infection induced pyroptosis along with NETosis in vitro, and depletion of either caspy2 or GSDMEb impaired NET formation in vivo. Consequently, inhibition of the caspy2-GSDMEb axis-gated NETosis impaired bacterial clearance in vivo. Altogether, these data provide evidence that teleost fish innate immune cells, including neutrophils, express features of pyroptosis that are critical for NETosis in teleost innate immunity. [ABSTRACT FROM AUTHOR]

Background: Glioblastoma (GBM) has a high degree of malignancy, aggressiveness and recurrence rate. However, there are limited options available for the treatment of GBM, and they often result in poor prognosis and unsatisfactory outcomes. Materials and methods: In order to identify potential core genes in GBM that may provide new therapeutic insights, we analyzed three gene chips (GSE2223, GSE4290 and GSE50161) screened from the GEO database. Differentially expressed genes (DEG) from the tissues of GBM and normal brain were screened using GEO2R. To determine the functional annotation and pathway of DEG, Gene Ontology (GO) and KEGG pathway enrichment analysis were conducted using DAVID database. Protein interactions of DEG were visualized using PPI network on Cytoscape software. Next, 10 Hub nodes were screened from the differentially expressed network using MCC algorithm on CytoHubba software and subsequently identified as Hub genes. Finally, the relationship between Hub genes and the prognosis of GBM patients was described using GEPIA2 survival analysis web tool. Results: A total of 37 up-regulated and 187 down-regulated genes were identified through microarray analysis. Amongst the 10 Hub genes selected, SV2B appeared to be the only gene associated with poor prognosis in glioblastoma based on the survival analysis. Conclusion: Our study suggests that high expression of SV2B is associated with poor prognosis in GBM patients. Whether SV2B can be used as a new therapeutic target for GBM requires further validation. [ABSTRACT FROM AUTHOR]

A 150 kJ/100 kW conduction-cooled HTS superconducting magnetic energy storage magnet, which consists of 17 double pancake coils and operates at 20 K, was developed and manufactured in the Huazhong University of Science and Technology. To evaluate the thermal characteristic of the magnet, this paper conducts a series of experiments and carries out the loss analyses. When the maintaining time and peak value of the flat top current in the magnet are constant, the maximum temperature rise will first decrease and then increase with the continuous augment of the current ramp rate, and it means that there is a valley value for the maximum temperature rise during an operational cycle time including charging, standby, and discharging stages. Similarly, the total losses, which include the ac heat loss and the resistive loss caused by the joints between every two double pancakes and extra resistance of the high temperature superconducting (HTS) coils, will fall with the increase of the ramp rate to its valley value, and then it will increase with the ramp rate. Experimental results show that the temperature variation of the magnet is in keeping with the heat loss variation. [ABSTRACT FROM AUTHOR]

The physical and chemical properties of V-M" and Nb-M" (M" is 3d or 4d transition metal) co-doped BaTiO3 were studied by first-principles calculation based on density functional theory. Our calculation results show that V-M"co-doping is more favorable than Nb-M" co-doping in terms of narrowing the bandgap and increasing the visible-light absorption. In pure BaTiO3, the bandgap depends on the energy levels of the Ti 3d and O 2p states. The appropriate co-doping can effectively manipulate the bandgap by introducing new energy levels interacting with those of the pure BaTiO3. The optimal co-doping effect comes from the V-Cr co-doping system, which not only has smaller impurity formation energy, but also significantly reduces the bandgap. Detailed analysis of the density of states, band structure, and charge-density distribution in the doping systems demonstrates the synergistic effect induced by the V and Cr co-doping. The results can provide not only useful insights into the understanding of the bandgap engineering by element doping, but also beneficial guidance to the experimental study of BaTiO3 for visible-light photoelectrical applications. [ABSTRACT FROM AUTHOR]

The electrochemical performance of supercapacitors might be associated with the homogeneous structure of the electrode materials. However, the relationship between the degree of uniformity for the electrode materials and the electrochemical performance of the supercapacitor is not clear. Herein, we synthesize two types of nickel bicarbonate nanocrystals with different degrees of uniformity to investigate this relationship. As the electroactive material, the nickel bicarbonate nanocrystals with a homogeneous structure could provide a larger space and offer more exposed atoms for the electrochemical reaction than the nanocrystals with a heterogeneous structure. The homogeneous nickel bicarbonate nanocrystals exhibit better electrochemical performance and show excellent specific capacitance (1596 F g−1 at 2 A g−1 and 1260 F g−1 at 30 A g−1), which is approximately twice that of the heterogeneous nickel bicarbonate nanocrystals. The cycling stability for the homogeneity (∼80%) is higher than the inhomogeneity (∼61%) at a high current density of 5 A g−1. [ABSTRACT FROM AUTHOR]

We develop a variational scheme called the "Gutzwiller renormalization group" (GRG), which enables us to calculate the ground state of Anderson impurity models (AIM) with arbitrary numerical precision. Our method exploits the low-entanglement property of the ground state of local Hamiltonians in combination with the framework of the Gutzwiller wave function and indicates that the ground state of the AIM has a very simple structure, which can be represented very accurately in terms of a surprisingly small number of variational parameters. We perform benchmark calculations of the single-band AIM that validate our theory and suggest that the GRG might enable us to study complex systems beyond the reach of the other methods presently available and pave the way to interesting generalizations, e.g., to nonequilibrium transport in nanostructures. [ABSTRACT FROM AUTHOR]

In this study, a novel environmentally friendly copolymer acrylic acid-itaconic acid-allylpolyethoxy maleic carboxylate was synthesized and used for inhibiting the calcium sulfate dehydrate (gypsum) scale. The properties of the synthesized copolymer were characterized by Fourier-transform infrared, nuclear magnetic resonance spectroscopy and thermal gravity analysis. Also, the structure and morphology changes of scale crystals were studied by scanning electronic microscopy, transmission electron microscopy and X-ray powder diffraction analysis. The copolymer inhibition ability was evaluated by means of static scale inhibition experiments. Results show that the copolymer was effective in inhibiting the scales by changing the size and morphology of the crystals. The maximum inhibition efficiency was 99.8% at a concentration of 2 mg · L-1, far more efficient than most commercial inhibitors. [ABSTRACT FROM AUTHOR]

The objectives of the current study were to isolate and identify the pathogen responsible for citrus canker and investigate the efficacy of sulfone derivatives containing 1,3,4-oxadiazole moiety on controlling citrus canker caused by Xanthomonas citri subsp. citri (Xcc) under in vitro and field conditions. In an in vitro study, we tested eight sulfone derivatives against Xcc and the results demonstrated that compound 3 exhibited the best antibacterial activity against Xcc, with a half-maximal effective concentration (EC50) value of 1.23 μg/mL, which was even better than those of commercial bactericides Kocide 3000 (58.21 μg/mL) and Thiodiazole copper (77.04 μg/mL), respectively. Meanwhile, under field experiments, compound 3 treatments demonstrated the highest ability to reduce the disease of citrus canker in leaves and fruits in two different places relative to an untreated control as well as the commercial bactericides Kocide 3000 and Thiodiazole copper. Meanwhile, compound 3 could stimulate the increase in peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) activities in the navel orange leaves, causing marked enhancement of plant resistance against citrus canker. Moreover, compound 3 could damage the cell membranes, destruct the biofilm formation, inhibit the production of extracellular polysaccharide (EPS), and affect the cell membrane permeability to restrain the growth of the bacteria. [ABSTRACT FROM AUTHOR]

We observe that Cu clusters grow on surface terraces of graphite as a result of physical vapor deposition in ultrahigh vacuum. We show that the observation is incompatible with a variety of models incorporating homogeneous nucleation and calculations of atomic-scale energetics. An alternative explanation, ion-mediated heterogeneous nucleation, is proposed and validated, both with theory and experiment. This serves as a case study in identifying when and whether the simple, common observation of metal clusters on carbon-rich surfaces can be interpreted in terms of homogeneous nucleation. We describe a general approach for making system-specific and laboratory-specific predictions. [ABSTRACT FROM AUTHOR]

Advanced materials characterization techniques with ever-growing data acquisition speed and storage capabilities represent a challenge in modern materials science, and new procedures to quickly assess and analyze the data are needed. Machine learning approaches are effective in reducing the complexity of data and rapidly homing in on the underlying trend in multi-dimensional data. Here, we show that by employing an algorithm called the mean shift theory to a large amount of diffraction data in high-throughput experimentation, one can streamline the process of delineating the structural evolution across compositional variations mapped on combinatorial libraries with minimal computational cost. Data collected at a synchrotron beamline are analyzed on the fly, and by integrating experimental data with the inorganic crystal structure database (ICSD), we can substantially enhance the accuracy in classifying the structural phases across ternary phase spaces.Wehave used this approach to identify a novel magnetic phase with enhanced magnetic anisotropy which is a candidate for rare-earth free permanent magnet. [ABSTRACT FROM AUTHOR]