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Red dwarfs are one of the smallest and dimmest main-sequence stars. With the improvement of observation technology, a rich population of planets have been discovered around them, which exhibits distinct distribution characteristics from the planets around Solar-like stars. Earth-like planets have a higher occurrence rate around red dwarfs, and the planetary systems are tightly compact. The closer habitable zone makes it easier to search for habitable planets. The distribution of the radius valley between super-Earths and sub-Neptunes also differs from that around solar-like stars. Moreover, the discovery of giant planets around these low-mass stars can be hard to explain by current leading theories of planet formation. As the mass of solid material in the protoplanetary disk decreases with decreasing stellar masses, the formation of giant planets remains challenging. The observations from telescopes such as Transiting Exoplanet Survey Satellite (TESS), James Webb, and Atacama Large Millimeter/submillimeter Array (ALMA) have provided invaluable insights and opportunities for the study of planetary formation. In this paper, we review the observations of different populations of planets and summarize the up-to-date understanding of planetary formation around red dwarfs. [ABSTRACT FROM AUTHOR]

Image segmentation is a significant step in image analysis and computer vision. Many entropy-based approaches have been presented on this topic. Among them, Tsallis entropy isone of the best-performing methods. In this paper, the surface defect images of galvanised steel sheets were studied. Atwo-dimensional asymmetric Tsallis cross-entropy image segmentation algorithm based on chaotic bee colony algorithm optimisation was used to investigate the segmentation of surface defects under complex texture backgrounds. On the basis of Tsallis entropy threshold segmentation, a more concise expression form was used to define the asymmetric Tsallis cross-entropy in order to reduce the calculation complexity of the algorithm. The chaotic algorithm was combined with the artificial bee colony (ABC) algorithm to construct the chaotic bee colony algorithm, so that the optimal threshold of Tsallis entropy could be quickly identified. The experimental results showed that compared with the maximum Shannon entropy algorithm, the calculation time of this algorithm decreased by about 58% and the threshold value increased by about (26%, 54%). Compared with the two-dimensional Tsallis cross-entropy algorithm, the calculation time of this algorithm decreased by about 35% and about 20% was improved in the g-axis direction only. Compared with the two-dimensional asymmetric Tsallis cross-entropy algorithm, the calculation time of this algorithm decreased by about 30% and the threshold values of the two algorithms were almost the same. The algorithm proposed in this paper can rapidly and effectively segment defect targets, making it a more suitable method for detecting surface defects in factories with a rapid production pace. [ABSTRACT FROM AUTHOR]

BACKGROUND: Although substantial evidence suggests that high and low temperatures are adversely associated with nonaccidental mortality, few studies have focused on exploring the risks of temperature on external causes of death. OBJECTIVES: We investigated the short-term associations between temperature and external causes of death and four specific categories (suicide, transport, falls, and drowning) in 47 prefectures of Japan from 1979 to 2015. METHODS: We conducted a two-stage meta-regression analysis. First, we performed time-stratified case-crossover analyses with a distributed lag nonlinear model to examine the association between temperature and mortality due to external causes for each prefecture. We then used a multivariate meta-regression model to combine the association estimates across all prefectures in Japan. In addition, we performed stratified analyses for the associations by sex and age. RESULTS: A total of 2,416,707 external causes of death were included in the study. We found a J-shaped exposure–response curve for all external causes of death, in which the risks increased for mild cold temperatures [20th percentile; relative risk (RR)= 1.09 (95% confidence interval [CI]: 1.05,1.12)] and extreme heat [99th percentile; RR = 1.24 (95% CI: 1.20, 1.29)] compared with those for minimum mortality temperature (MMT). However, the shapes of the exposure–response curves varied according to four subcategories. The risks of suicide and transport monotonically increased as temperature increased, with RRs of 1.35 (95% CI: 1.26, 1.45) and 1.60 (95% CI: 1.35, 1.90), respectively, for heat, whereas J- and U-shaped curves were observed for falls and drowning, with RRs of 1.14 (95% CI: 1.03, 1.26) and 1.95 (95% CI: 1.70, 2.23) for heat and 1.13 (95% CI: 1.02, 1.26) and 2.33 (95% CI: 1.89, 2.88) for cold, respectively, compared with those for cause-specific MMTs. The sex- and age-specific associations varied considerably depending on the specific causes. DISCUSSION: Both low and high temperatures may be important drivers of increased risk of external causes of death. We suggest that preventive measures against external causes of death should be considered in adaptation policies. [ABSTRACT FROM AUTHOR]

M dwarf is not only one of the lowest mass stars in the main sequence stars, but also the most numerous stars in the Milky Way. Planets and habitable zones around M dwarfs are usually closer to their host stars than F, G, and K-type stars, so it is more convenient for us to discover new planets and observe habitable planets. On average, there are 2.5 low-mass planets orbiting around each M dwarf, which is about 3.5 times that of F, G, and K stars, while the occurrence rate of giant planets, which greatly depends on the metallicity of their host stars, is one order of magnitude lower than that of F, G, and K stars. Herein we apply a set of selection criteria to collect 401 planets around M dwarfs to investigate the property of planets. Statistical analysis shows that terrestrial planets, whose semi-major axes are less than 1 au, account for about 74% of the total number of planets. About twenty-eight Earth-sized planets orbit within the habitable zone of their stars, which means that there might be liquid water and atmosphere on planet surface. In addition, the average distance between planets and their host stars tends to increase with the masses of planets. According to the planetary mass-radius relationship, there is a turning point at 4 M ⊕ (mass of Earth). With few exceptions, most planets with mass < 4 M ⊕ may be composed of 65% silicate and 35% iron, otherwise the radius of planet grows rapidly with the increase of mass because of a substantial gaseous envelope. Approximately 60% planets around M dwarfs are in tightly packed planetary systems, whose orbital configuration is observed to be trapped into 3: 2, 5: 3, and 2: 1 mean motion resonances. To explain the formation of compact system, several scenarios have been proposed, for instance inside-out formation and pebble-driven planet formation, even though the initial position of planetary embryos remains ambiguous. The formation of giant planets around low-mass stars also challenges the existing planet formation theory. Fortunately, high precision and resolution observation of space and ground-based telescopes is unveiling the structure of protoplanetary disks gradually, which offers the crucial initial conditions of planet formation, as well as the observation of planetary atmospheric composition. [ABSTRACT FROM AUTHOR]

Membrane lipid remodelling is one of the strategies that plants have developed to combat abiotic stress. In this study, physiological, lipidomic and proteome analyses were conducted to investigate the changes in glycerolipid and phospholipid concentrations in the wheat (Triticum aestivum L.) cultivars CIGM90.863 and Seri M82 under hypoxia treatment. The growth of CIGM90.863 remained unaffected, whereas Seri M82 was significantly stunted after 8 days of hypoxia treatment. The concentrations of all lipids except lysophosphatidylglycerol were significantly higher in the leaves of Seri M82 than in CIGM90.863 under normal growth conditions. The lipid profile changed significantly under hypoxia stress and varied between genotypes for some of the lipids. Phosphatidic acids remained unchanged in Seri M82 but they were gradually induced in CIGM90.863 in response to hypoxia stress because of the higher phospholipaseDexpression and lower expression of diglycerol kinase and phosphatidate phosphatases. In contrast, digalactosyldiacylglycerol content was highly stable in CIGM90.863 following hypoxia treatment, although it decreased significantly in Seri M82. Phosphatidylglycerol and lipoxygenase showed a stronger and faster response in CIGM90.863 than in Seri M82 under hypoxia stress. Different membrane lipid adjustments in wheat under oxygen deficiency conditions could be partly responsible for the differing tolerance of SeriM82and CIGM90.863. This study will help us to better understand howwheat tolerates hypoxia stress by regulating lipid remodelling. [ABSTRACT FROM AUTHOR]

One type of orbital angular momentum (OAM) reflectarray antenna is presented to radiate the electromagnetic wave with beam vorticity. Microstrip double square loops are adopted as the element for the proposed reflectarray. Reflect phase of the elements with various sizes are analyzed by HFSS software with periodic boundary condition and Floquet mode. Then massive elements with different sizes are arranged helically to form the reflectarray, transforming the incident spherical wave into a vortex phase front. Several OAM reflectarray examples with different OAM mode and different feed mode are designed and fabricated. The phase patterns of far-zone field are simulated by FEKO software and measured by near-field scanning system, which demonstrates the phase singularity and vortex. [ABSTRACT FROM AUTHOR]

A cascade three-component iodoazidation of para-quinone methides to construct spiro[4.5]deca-6,9-dien-8-ones under mild conditions has been developed. The chemoselective 1,6-addition of azide radical triggered a regioselective 5-exo-dig cyclization/radical coupling sequence, enabling C–N, C–C, and C–I bond formations in a one-pot procedure with high efficiency. [ABSTRACT FROM AUTHOR]

Recently, the chiral-induced spin selectivity in molecular systems has attracted extensive interest among the scientific communities. Here, we investigate the effect of the gate voltage on spin-selective electron transport through the α-helical peptide/protein molecule contacted by two nonmagnetic electrodes. Based on an effective model Hamiltonian and the Landauer-Büttiker formula, we calculate the conductance and the spin polarization under an external electric field, which is perpendicular to the helix axis of the α-helical peptide/protein molecule. Our results indicate that both the magnitude and the direction of the gate field have a significant effect on the conductance and the spin polarization. The spin filtration efficiency can be improved by properly tuning the gate voltage, especially in the case of the strong dephasing regime. And the spin polarization increases monotonically with the molecular length without the gate voltage, which is consistent with the recent experiment, and presents oscillating behavior in the presence of the gate voltage. In addition, the spin selectivity is robust against the dephasing, the on-site energy disorder, and the space angle disorder under the gate voltage. Our results could motivate further experimental and theoretical works on the chiral-based spin selectivity in molecular systems. [ABSTRACT FROM AUTHOR]

A compressed terahertz imaging method using a terahertz time domain spectroscopy system (THz-TDSS) is suggested and demonstrated. In the method, a parallel THz wave with the beam diameter 4 cm from a usual THz-TDSS is used and a square shaped 2D echelon is placed in front of an imaged object. We confirm both in simulation and in experiment that only one terahertz time domain spectrum is needed to image the object. The image information is obtained from the compressed THz signal by deconvolution signal processing, and therefore the whole imaging time is greatly reduced in comparison with some other pulsed THz imaging methods. The present method will hopefully be used in real-time imaging. [ABSTRACT FROM AUTHOR]

Six new coordination compounds, namely [Co(H2bptc)]n(1), [Mn(H2bptc)]n(2), [Cd2(bptc)(phen)2(H2O)2]n(3), [Eu2(cpa)3(DMF)2]n(4), [Nd2(cpa)3(DMF)2]n(5) and [Pr2(cpa)3(DMF)2]n(6) (bptc4−= biphenyl-2,2′,4,4′-tetracarboxylate anion, phen =1,10-phenanthroline, cpa2−= 4-chloroisophthalic acid anion) were synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, and thermogravimetric analysis. Co and Mn compounds are isostructural, and possess a three-dimensional 5, 5-connected network. In Cd compound, multicarboxylate ligand H4bptc link Cd centers to generate a two-dimensional 4, 4-cnet structure with phen acting as terminal ligand. Eu, Nd, and Pr compounds have similar structures, and cpa2−ligands link lanthanide cations to generate a two-dimensional sheet structure. Magnetic susceptibility measurements indicate that the Co compound has a dominating ferromagnetic coupling between Co(ii) ions, and Mn compound exhibits antiferromagnetic coupling between Mn(ii) ions. Furthermore, their luminescent properties are also determined in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

Hypoxic tissue has been observed in the surrounding areas of the ischemic core following cerebral infarction. The underlying mechanisms for this potentially reversible ischemic region remain to be determined. In this study, we generated permanent brain ischemia (PI) and reperfusion after inducing ischemia for 1.5 h (ischemia–reperfusion or IR) in a rat model of middle cerebral artery occlusion. Using immunofluorescence, we observed hypoxic tissue in ischemic brains and assessed microvessel density in and surrounding the hypoxic tissue. We found that the hypoxic tissues were observed at 1 and 3 days in PI rats and at 1, 3, 7, and 14 days in IR rats. The hypoxic tissue gradually decreased over time. The microvessel density increased in a time-dependent manner in focal brain ischemic tissue in PI and IR rats. Furthermore, IR induced a significant increase in microvessel density when compared with PI rats (P < 0.05). Microvessel density surrounding hypoxic tissue was significantly higher when compared with within the hypoxic tissue (P < 0.05). These data demonstrate that hypoxic tissue may exist for a long period (14 days) following brain IR and indicate that hypoxic tissue usually existed with low microvessel density. Furthermore, the duration of hypoxic tissue was partially dependent on the degree of microvessel proliferation. [ABSTRACT FROM AUTHOR]

Pulsatile stress is defined as product of pulse pressure (PP) and heart rate (HR) and is largely regulated by arterial stiffness in general and specifically with reference to patients with renal insufficiency by sympathetic nerve activity. Direct effects of the pulsatile stress on heart, coronary system and ultimately cardiovascular survival have been documented whereas no data exist relating to renal transplant patients. We analysed the relation of macrocirculatory disturbance to microcirculatory defects in 92 renal transplant recipients. Therefore, we investigated aortic stiffness by carotid-femoral pulse wave velocity (PWV), pulsatile stress and albuminuria. Pulsatile stress, not PWV was associated with the extent of albuminuria ( r = 0.29; P < 0.01 and r = 0.06; P = 0.6 respectively), which was confirmed in multivariate stepwise regression analysis ( P = 0.008). Dividing the data in tertiles of pulsatile stress revealed an eightfold increased risk for microalbuminuria and 12.2-fold increased risk for macroalbuminuria comparing upper with lower tertile of pulsatile stress. Pulsatile stress, not PWV correlates with albuminuria and predicts the degree of albuminuria in renal transplant recipients. Therefore, pulsatile stress reflects an easy and cost-effective marker for renal microcirculatory defects in renal transplant patients. [ABSTRACT FROM AUTHOR]

Two new 3D frameworks [(WS4Cu6Br4)(timp)8/3(H2O)40/3]n(1) and [(WS4Cu6Br4) (timtz)8/3(H2O)40/3]n(2), containing heptanuclear cluster blocks (one W atom and six Cu atoms) bridged by trigonal ligands timp or timtz (timp = 1-(3,5-di (1H-imidazol-1-yl)phenyl)-1H-imidazole; timtz = 2,4,6-tri(1H-imidazol-1-yl)-1,3,5-triazine), were successfully synthesized. Both compounds were characterized by single-crystal X-ray diffraction, elemental analysis, XRD, IR, TGA. X-ray determination shows that 1and 2can be topologically represented as (3,4)-connected networks with α-C3N4(or ctn) topology where [WS4Cu6] act as the 4-connecting nodes, and the timp or timtz ligands bridge in pairs that act as the three-connecting nodes. Both compounds have the high symmetry of space group I-43d, which is the maximum symmetry for this net topology. The luminescent spectra and N2absorption behaviors for 1and 2have also been investigated. [ABSTRACT FROM AUTHOR]

In this paper, an event-triggered antidisturbance (ETAD) control scheme is presented for a category of aeroengine control systems (AECSs) involved in multiple disturbances. First, an AECS in this category is described by a switched model at a series of steady-state points. Then, a dynamic event-triggered mechanism is introduced by constructing the ET condition based on the control input directly, saving the signal transmission resource from the controller to the AECS. Next, a switching law with sampling is developed, economizing the signal transmission resource from the switching law to the AECS. Furthermore, based on the ET mechanism and switching law, an antidisturbance controller is designed to compensate for or suppress the influence of the multiple disturbances on the AECS. Also, under the ETAD control approach, relative theoretical conditions are established to save the signal transmission resource and to suppress or compensate multiple disturbances. Finally, using a hardware-in-loop platform with a switched aeroengine model inserted, a simulation is implemented to validate how the established ETAD control strategy is effectively applied to the AECS. [ABSTRACT FROM AUTHOR]

Introduction: MicroRNAs (miRs) are small noncoding RNAs which are regulators of gene expression and also regulate the genes in heart tissues. The aim of the study was to evaluate the effect of miRs on the expression level of myosin heavy chain (MHC), which is responsible for regulation of cardiac functions in neonatal rat ventricular myocytes and mice. Material and methods: The miRs were suppressed in neonatal rat ventricular myocytes using small interfering RNAs (siRNAs) against Dicer followed by evaluation of MHC levels. For in vivo study the C57 black/6 Jacksonian mice were subjected to the transverse aortic constriction (TAC) procedure. Results: The Dicer siRNA suppressed the endogenous miRs and the α-MHC gene but failed to down-regulate the β-MHC. Among the 17 selected miRs, miR-29a was found to up-regulate the α-MHC gene significantly but not β-MHC. The expression of α-MHC was suppressed by silencing the expression of miR-29a. Bioinformatics study done by TargetScan suggested thyroid hormone receptor-β1 (TR-β1) as a potential target of miR-29a. Additionally, miR-29a was found to regulate the expression of α-MHC via TR-β1 signaling. Conclusions: The findings of the present study indicated that miR-29a modulates expression of α-the MHC gene by targeting TR-β1 in cardiac cells. The study may provide a new direction for treating cardiac failure and cardiac hypertrophy. [ABSTRACT FROM AUTHOR]

Glutathione S-transferases (GSTs) are proteins synthesized in plants and responsible for their tolerance to environmental stresses. However, little information is available on the GST gene family of sweet potato, a globally important crop. The genetic evolution of GSTs in sweet potato remains unclear. The present study investigated the GST gene family in sweet potato by transcriptomic and comparative genomic analyses. A total of 51 GSTs were identified. Gene expression analysis showed differential expression patterns of the GSTs between two investigated varieties. Some GST expression levels were either up- or downregulated under oxidative, salinity and drought stresses. The results of the investigation provided new insights on the GST gene family in sweet potato, which may further the understanding of the roles of these genes in regulating abiotic stresses. [ABSTRACT FROM AUTHOR]

Stochastic thermodynamics provides an important framework to explore small physical systems where thermal fluctuations are inevitable. In the studies of stochastic thermodynamics, some thermodynamic quantities, such as the trajectory work, associated with the complete Langevin equation (the Kramers equation) are often assumed to converge to those associated with the overdamped Langevin equation (the Smoluchowski equation) in the overdamped limit under the overdamped approximation. Nevertheless, a rigorous mathematical proof of the convergence of the work distributions to our knowledge has not been reported so far. Here we study the convergence of the work distributions explicitly. In the overdamped limit, we rigorously prove the convergence of the extended Fokker-Planck equations including work using a multiple timescale expansion approach. By taking the linearly dragged harmonic oscillator as an exactly solvable example, we analytically calculate the work distribution associated with the Kramers equation, and verify its convergence to that associated with the Smoluchowski equation in the overdamped limit. We quantify the accuracy of the overdamped approximation as a function of the damping coefficient. In addition, we experimentally demonstrate that the data of the work distribution of a levitated silica nanosphere agrees with the overdamped approximation in the overdamped limit, but deviates from the overdamped approximation in the low-damping case. Our work fills a gap between the stochastic thermodynamics based on the complete Langevin equation (the Kramers equation) and the overdamped Langevin equation (the Smoluchowski equation), and deepens our understanding of the overdamped approximation in stochastic thermodynamics. [ABSTRACT FROM AUTHOR]

Feynman’s ratchet is a microscopic machine in contact with two heat reservoirs, at temperatures TA and TB, that was proposed by Richard Feynman to illustrate the second law of thermodynamics. In equilibrium (TA = TB), thermal fluctuations prevent the ratchet from generating directed motion. When the ratchet is maintained away from equilibrium by a temperature difference (), it can operate as a heat engine, rectifying thermal fluctuations to perform work. While it has attracted much interest, the operation of Feynman’s ratchet as a heat engine has not been realized experimentally, due to technical challenges. In this work, we realize Feynman’s ratchet with a colloidal particle in a one-dimensional optical trap in contact with two heat reservoirs: one is the surrounding water, while the effect of the other reservoir is generated by a novel feedback mechanism, using the Metropolis algorithm to impose detailed balance. We verify that the system does not produce work when TA = TB, and that it becomes a microscopic heat engine when . We analyze work, heat and entropy production as functions of the temperature difference and external load. Our experimental realization of Feynman’s ratchet and the Metropolis algorithm can also be used to study the thermodynamics of feedback control and information processing, the working mechanism of molecular motors, and controllable particle transportation. [ABSTRACT FROM AUTHOR]

Nonequilibrium processes of small systems such as molecular machines are ubiquitous in biology, chemistry, and physics but are often challenging to comprehend. In the past two decades, several exact thermodynamic relations of nonequilibrium processes, collectively known as fluctuation theorems, have been discovered and provided critical insights. These fluctuation theorems are generalizations of the second law and can be unified by a differential fluctuation theorem. Here we perform the first experimental test of the differential fluctuation theorem using an optically levitated nanosphere in both underdamped and overdamped regimes and in both spatial and velocity spaces. We also test several theorems that can be obtained from it directly, including a generalized Jarzynski equality that is valid for arbitrary initial states, and the Hummer-Szabo relation. Our study experimentally verifies these fundamental theorems and initiates the experimental study of stochastic energetics with the instantaneous velocity measurement. [ABSTRACT FROM AUTHOR]

Recently, the spin-selectivity effect of chiral molecules has been attracting extensive and growing interest among the scientific communities. Here, we propose a model Hamiltonian to study spin-dependent electron transport through helicene molecules which are connected by two semi-infinite graphene nanoribbons and try to elucidate a recent experiment of the spin-selectivity effect observed in the helicene molecules. The results indicate that the helicene molecules can present a significant spin-filtering effect in the case of extremely weak spin-orbit coupling, which is three orders of magnitude smaller than the hopping integral. The underlying physics is attributed to intrinsic chiral symmetry of the helicene molecules. When the chirality is switched from the right-handed species to the left-handed species, the spin polarization is reversed exactly. These results are consistent with a recent experiment [V. Kiran et al., Adv. Mater. 28, 1957 (2016)]. In addition, the spin-filtering effect of the helicene molecules is robust against molecular lengths, dephasing strengths, and space position disorder. This theoretical work may motivate further studies on chiral-induced spin selectivity in molecular systems. [ABSTRACT FROM AUTHOR]

Recently, chiral-induced spin selectivity has been attracting intense interest. Here, we report a theoretical study of spin-dependent electron transport in achiral nanotubes contacted by nonmagnetic leads. Our results reveal that by properly connecting to the leads, the achiral nanotubes can present a pronounced spin filtering phenomenon even if the spin-orbit coupling is very weak. In addition, the spin selectivity effect holds for various achiral nanotubes with different radii and is still significant in the presence of strong disorder and dephasing. These findings open new opportunities of using achiral molecules in spintronic applications and could motivate further studies on spin transport along achiral systems. [ABSTRACT FROM AUTHOR]

An unprecedented silver-catalyzed cascade 1,6-addition/5-exo-dig cyclization reaction between para-quinone methides and propargyl malonates under mild reaction conditions has been described. This reaction provides an efficient method to construct versatile spiro[4.5]cyclohexadienones in moderate to excellent yields with high atom economy and scalability. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, [Ni(C6H4N2O4S)(H2O)3]·2.5H2O, the NiII atom is six-coordinated by one 2-(6-oxido-4-oxo-3,4-dihydro­pyimidin-2-ylsulfan­yl)­acetate ligand and three water mol­ecules. Hydrogen-bonding inter­actions between the coordinated and uncoordinated water mol­ecules and between the water mol­ecules and the organic ligand result in a three-dimensional network structure. [ABSTRACT FROM AUTHOR]

In the title compound, {[Co(C8H4O5)(C10H8N2)]·2H2O]} n or {[Co(OH-BDC)(2,2′-bipy)]·2H2O]} n (where OH-H2BDC is 5-hydroxy­isophthalic acid and 2,2′-bipy is 2,2′-bipyridine), the Co atoms are chelated by two N atoms from the 2,2′-bipy ligand and by four O atoms from OH-BDC ligands in a highly distorted octa­hedral geometry. OH-BDC acts as a tetra­dentate ligand, with one carboxyl­ate group chelating one Co atom and the other binding in a monodentate fashion to two other Co atoms to form a one-dimensional zigzag chain. In the crystal structure, one of the solvent water mol­ecules lies on a crystallographic twofold axis. The one-dimensional mol­ecular chains are assembled into a two-dimensional network via O—H⋯O hydrogen-bonding inter­actions, while π–π stacking inter­actions generate a three-dimensional open framework between the two-dimensional networks. [ABSTRACT FROM AUTHOR]

Facile, straightforward, and asymmetric total syntheses of (+)-chimonanthine (1), (+)-folicanthine (2), and (−)-calycanthine (3) were accomplished in four to five steps from commercially available tryptamine. The synthesis features copper-mediated asymmetric cyclodimerization of chiral tryptamine derivative, which established a new entry into constructing the sterically hindered vicinal quaternary stereogenic carbon centers of dimeric hexahydropyrroloindole alkaloids in one procedure. An unprecedented base-induced isomerization from the chimonanthine skeleton to the calycanthine skeleton was observed and facilitated the synthesis of (−)-calycanthine (3). [ABSTRACT FROM AUTHOR]

Buried pipelines are commonly damaged when laid across strike-slip faults, always leading to some level of destruction with fault movement. The moment of the neutral axis of a pipe section was obtained by integration, and the equations for the bending moment and the bending strain on a pipeline's section were presented here, based on a trilinear stress-strain model. The calculation method for the lateral soil pressure and pipeline's bending strain near the fault-crossing point was improved. Lateral soil pressure was regarded as being related to lateral pipeline movement and, for accurate calculation, this part of the pipeline was divided into finite element segments. An iterative process for solving for pipe bending strain was derived, and the algorithm and program for calculating bending strain and the potential damage position of the pipeline's sections was compiled based on Matlab software. Compared with finite element method (FEM) results and the current standard method, in the situation of a pipeline being in tension under the action of a strike-slip fault (intersection angle < 90°), the result of the proposed method is in good agreement with FEM results. This shows that the proposed analytical method possessed a good reference value for the strain response analysis of tensile steel pipelines under strike-slip faulting. [ABSTRACT FROM AUTHOR]

The self-assembly of 3,5-pyrazoledicarboxylic acid (H3pdc) and metal salts under hydrothermal conditions leads to the formation of a series of novel NaI–CuII–LnIII heterometallic coordination polymers, {[Na(H2O)4]2[Cu(pdc)2Ln(H2O)5]2·3H2O}n [Ln = La (1); Sm (2); Pr (3); Nd (4) and pdc3− = 3,5-pyrazoledicarboxylate]. X-Ray structure analyses show that these complexes all exhibit pairs of infinite, unexpected, cationic and anionic chains. It is the first successful attempt to construct unprecedented NaI–CuII–LnIII heterometallic coordination polymers with both infinite cationic and anionic chains. These four complexes show homologous thermal stabilities. The different magnetic properties of 1–3 are also been reported in this paper. [ABSTRACT FROM AUTHOR]

Entropy is one of the most basic concepts in thermodynamics and statistical mechanics. The most widely used definition of statistical mechanical entropy for a quantum system is introduced by von Neumann. While in classical systems, the statistical mechanical entropy is defined by Gibbs. The relation between these two definitions of entropy is still not fully explored. In this work, we study this problem by employing the phase-space formulation of quantum mechanics. For those quantum states having well-defined classical counterparts, we study the quantum-classical correspondence and quantum corrections of the entropy. We expand the von Neumann entropy in powers of ℏ by using the phase-space formulation, and the zeroth-order term reproduces the Gibbs entropy. We also obtain the explicit expression of the quantum corrections of the entropy. Moreover, we find that for the thermodynamic equilibrium state, all terms odd in ℏ are exactly zero. As an application, we derive quantum corrections for the net work extraction during a quantum Carnot cycle. Our results bring important insights into the understanding of quantum entropy and may have potential applications in the study of quantum heat engines. [ABSTRACT FROM AUTHOR]

Work statistics characterizes important features of a nonequilibrium thermodynamic process, but the calculation of the work statistics in an arbitrary nonequilibrium process is usually a cumbersome task. In this work, we study the work statistics in quantum systems by employing Feynman's path-integral approach. We derive the analytical work distributions of two prototype quantum systems. The results are proved to be equivalent to the results obtained based on Schrödinger's formalism. We also calculate the work distributions in their classical counterparts by employing the path-integral approach. Our study demonstrates the effectiveness of the path-integral approach for the calculation of work statistics in both quantum and classical thermodynamics, and brings important insights to the understanding of the trajectory work in quantum systems. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pesticides have been associated with reproductive disorders, but there is limited research on pesticide exposures and human fertility. OBJECTIVE: We aimed to investigate the effects of preconception exposure to pesticides on time to pregnancy (TTP) and on infertility in a general population of couples planning to become pregnant in Shanghai, China. METHODS: A total of 615 women who were planning a pregnancy were enrolled before conception and were prospectively followed for 1 y to observe their TTP. Preconception pesticide exposures were assessed by measuring urinary metabolites of organophosphates (OPs) and pyrethroids (PYRs). Fecundability odds ratios (FORs) and odds ratios (ORs) of infertility were estimated using Cox and logistic regression models, respectively. All analyses were repeated after restricting the sample to nulliparous women (n=569). RESULTS: After adjusting for age, prepregnancy BMI, current smoking, education, annual household income, age at menarche, and two items from the Perceived Stress Scale (PSS-10), women in the highest quartile of diethylthiophosphate (DETP; an OP metabolite) had significantly longer TTP [adjusted FOR=0:68 (95% CI: 0.51, 0.92)] and increased infertility [adjusted OR=2:17 (95% CI: 1.19, 3.93)] compared with women in the lowest quartile. The highest versus lowest quartile of 3-phenoxybenzoic acid (3PBA; a PYR metabolite) was associated with longer TTP and infertility, with significant associations in nulliparous women [adjusted FOR=0:72 (95% CI: 0.53, 0.98); adjusted OR for infertility=2:03 (95% CI: 1.10, 3.74)]. CONCLUSION: Our study provides some of the first evidence that preconception OP and PYR exposures are associated with decreased fertility in Chinese couples. Given that OPs and PYRs are rapidly metabolized in humans, more studies are needed to confirm our findings. [ABSTRACT FROM AUTHOR]

Selective growth of either monolayer or bilayer graphene is of great importance. We developed a method to readily tune large area graphene growth from complete monolayer to complete bilayer. In an ambient pressure chemical vapor deposition process, we used the sample temperature at which to start the H2 flow as the control parameter and realized the change from monolayer to bilayer growth of graphene on Cu foil. When the H2 starting temperature was above 700°C, continuous monolayer graphene films were obtained. When the H2 starting temperature was below 350°C, continuous bilayer films were obtained. Detailed characterization of the samples treated under various conditions revealed that heating without the H2 flow caused Cu oxidation. The more the Cu substrate oxidized, the less graphene bilayer could form. [ABSTRACT FROM AUTHOR]

MicroRNA-215 (miR-215) has previously been demonstrated to be dysregulated in a number of human malignancies and to be correlated with tumor progression. However, the expression and function of miR-215 in non-small cell lung cancer (NSCLC) has remained to be elucidated. Therefore, the present study aimed to investigate the effects of miR-215 in NSCLC tumorigenesis and development. Reverse transcription- quantitative polymerase chain reaction was used to evaluate miR-215 expression in NSCLC cell lines and primary tumor tissues. The association between miR-215 expression and certain clinicopathological factors was also determined, and the effects of miR-215 on the biological behavior of NSCLC cells were investigated. In addition, the potential regulatory function of miR-215 on zinc finger E-box-binding homeobox 2 (ZEB2) expression was examined. miR-215 expression was significantly downregulated in NSCLC cell lines and clinical specimens. Reduced miR-215 expression was significantly associated with lymph node metastasis and advanced TNM stage. Overexpression of miR-215 inhibited NSCLC cell proliferation, invasion and migration, and promoted cell apoptosis in vitro, and suppressed tumorigenicity in vivo. Furthermore, luciferase reporter assay analysis identified ZEB2 as a direct target of miR-215. These findings indicated that miR-215 may act as a tumor suppressor in NSCLC and may serve as a novel therapeutic agent for miR-based therapy. [ABSTRACT FROM AUTHOR]

Background: Overweight and obesity are epidemic worldwide. The purpose of this research is to estimate whether the prevalence of obesity among primary school children is high, and to identify its potential determinants to optimize the methods of prevention to combat further increases in childhood overweight. Methods: A cross-sectional study was designed to collect the routine health screening data for primary school children in Wannan area, China. Overweight and obesity status were determined using the International Obesity Task Force standard (IOTF) BMI cut-off points. Results: A total of 67956 subjects (36664 male and 31292 female) aged 5-14 years were recruited in this study. Depending on the references used (IOTF), the overall prevalence of overweight, including obesity of the subjects was 17.85 % , the prevalence of overweight, including obesity was 22.9% in male subjects and 11.9% in female subjects, respectively. The overall prevalence of obesity was3.7%, the prevalence of obesity was 5.2 % in male subjects and 1.8% in female subjects, respectively. An interesting observation made was that the prevalence of overweight was high in male subjects. Conclusions: Overweight is prevalence among primary school children, especially in male children. The relate department of school and government should take some measure to reduce the prevalence of overweight and obesity. [ABSTRACT FROM AUTHOR]