Radiocarbon releases from the 2011 Fukushima nuclear accident

Radiocarbon activities were measured in annual tree rings for the years 2009 to 2015 from Japanese cedar trees (Cryptomeria japonica) collected at six sites ranging from 2.5–38 km northwest and north of the Fukushima Dai-ichi nuclear power plant. The 14C specific activity varied from 280.4 Bq kg−1 C in 2010 to 226.0 Bq kg−1 C in 2015. The elevated 14C activities in the 2009 and 2010 rings confirmed 14C discharges during routine reactor operations, whereas those activities that were indistinguishable from background in 2012–2015 coincided with the permanent shutdown of the reactors after the accident in 2011. High-resolution 14C analysis of the 2011 ring indicated 14C releases during the Fukushima accident. The resulted 14C activity decreased with increasing distance from the plant. The maximum 14C activity released during the period of the accident was measured 42.4 Bq kg−1 C above the natural ambient 14C background. Our findings indicate that, unlike other Fukushima-derived radionuclides, the 14C released during the accident is indistinguishable from ambient background beyond the local environment (~30 km from the plant). Furthermore, the resulting dose to the local population from the excess 14C activities is negligible compared to the dose from natural/nuclear weapons sources

Low Mach number effect in simulation of high Mach number flow

In this note, we relate the two well-known difficulties of Godunov schemes: the carbuncle phenomena in simulating high Mach number flow, and the inaccurate pressure profile in simulating low Mach number flow. We introduced two simple low-Mach-number modifications for the classical Roe flux to decrease the difference between the acoustic and advection contributions of the numerical dissipation. While the first modification increases the local numerical dissipation, the second decreases it. The numerical tests on the double-Mach reflection problem show that both modifications eliminate the kinked Mach stem suffered by the original flux. These results suggest that, other than insufficient numerical dissipation near the shock front, the carbuncle phenomena is strongly relevant to the non-comparable acoustic and advection contributions of the numerical dissipation produced by Godunov schemes due to the low Mach number effect.Comment: 9 pages, 1 figur

The in vivo Therapeutic Effect of Free Wanderer Powder (逍 遙 散 xiāo yáo sǎn, Xiaoyaosan) on Mice with 4T1 Cell Induced Breast Cancer Model

ABSTRACTIn the present study, we investigated the therapeutic effect of a classical TCM formula, Free Wanderer Powder (逍遙散 xiāo yáo sǎn), in a breast cancer mouse model induced with estrogen-insensitive breast cancer 4T1 cells. Ovariectomized Balb/c mice (6-8 weeks) or sham mice were injected into the fourth mammary fat pad with 4T1 cells in which tumors were palpable 7days after injection. On the eighth day, the mice were divided into 4 groups and tubefed daily with vehicle, Free Wanderer Powder (逍遙散 xiāo yáo sǎn) formula or tamoxifen for 28days. Tumor growth inhibition and the decrease of the average tumor mass were most evident in mice treated with Free Wanderer Powder (逍遙散 xiāo yáo sǎn). Free Wanderer Powder (逍遙散 xiāo yáo sǎn) treatment significantly reduced Bcl-2 and elevated Bax and p53 protein expressions in breast cancer tumor. These results were further confirmed by immunohistochemisty. Tamoxifen could decrease spleen mass and Bcl-2 protein expression, increase the Bax protein expression as well as exert uterotrophic effects by increasing uterus index and inducing the gene expressions in the uterus. Taken together, these results show that Free Wanderer Powder (逍遙散 xiāo yáo sǎn) treatment induced apoptosis at protein level and inhibited the tumor growth in 4T1-induced ovariectomized Balb/c female mice, indicating the possibility of its future use for treatment of estrogen-insensitive breast caner

Modulation of mouse neural crest cell motility by N-cadherin and connexin 43 gap junctions

Connexin 43 (Cx43α1) gap junction has been shown to have an essential role in mediating functional coupling of neural crest cells and in modulating neural crest cell migration. Here, we showed that N-cadherin and wnt1 are required for efficient dye coupling but not for the expression of Cx43α1 gap junctions in neural crest cells. Cell motility was found to be altered in the N-cadherin–deficient neural crest cells, but the alterations were different from that elicited by Cx43α1 deficiency. In contrast, wnt1-deficient neural crest cells showed no discernible change in cell motility. These observations suggest that dye coupling may not be a good measure of gap junction communication relevant to motility. Alternatively, Cx43α1 may serve a novel function in motility. We observed that p120 catenin (p120ctn), an Armadillo protein known to modulate cell motility, is colocalized not only with N-cadherin but also with Cx43α1. Moreover, the subcellular distribution of p120ctn was altered with N-cadherin or Cx43α1 deficiency. Based on these findings, we propose a model in which Cx43α1 and N-cadherin may modulate neural crest cell motility by engaging in a dynamic cross-talk with the cell's locomotory apparatus through p120ctn signaling

Identifying a Universal Activity Descriptor and a Unifying Mechanism Concept on Perovskite Oxides for Green Hydrogen Production

Producing indispensable hydrogen and oxygen for social development via water electrolysis shows more prospects than other technologies. Although electrocatalysts have been explored for centuries, a universal activity descriptor for both hydrogen-evolution reaction (HER) and oxygen-evolution reaction (OER) is not yet developed. Moreover, a unifying concept is not yet established to simultaneously understand HER/OER mechanisms. Here, the relationships between HER/OER activities in three common electrolytes and over ten representative material properties on 12 3d-metal-based model oxides are rationally bridged through statistical methodologies. The orbital charge-transfer energy (Δ) can serve as an ideal universal descriptor, where a neither too large nor too small Δ (≈1 eV) with optimal electron-cloud density around Fermi level affords the best activities, fulfilling Sabatier's principle. Systematic experiments and computations unravel that pristine oxide with Δ ≈ 1 eV possesses metal-like high-valence configurations and active lattice-oxygen sites to help adsorb key protons in HER and induce lattice-oxygen participation in the OER, respectively. After reactions, partially generated metals in the HER and high-valence hydroxides in the OER dominate proton adsorption and couple with pristine lattice-oxygen activation, respectively. These can be successfully rationalized by the unifying orbital charge-transfer theory. This work provides the foundation of rational material design and mechanism understanding for many potential applications

Strongly coupled slow-light polaritons in one-dimensional disordered localized states

Cavity quantum electrodynamics advances the coherent control of a single quantum emitter with a quantized radiation field mode, typically piecewise engineered for the highest finesse and confinement in the cavity field. This enables the possibility of strong coupling for chip-scale quantum processing, but till now is limited to few research groups that can achieve the precision and deterministic requirements for these polariton states. Here we observe for the first time coherent polariton states of strong coupled single quantum dot excitons in inherently disordered one-dimensional localized modes in slow-light photonic crystals. Large vacuum Rabi splittings up to 311.μeV are observed, one of the largest avoided crossings in the solid-state. Our tight-binding models with quantum impurities detail these strong localized polaritons, spanning different disorder strengths, complementary to model-extracted pure dephasing and incoherent pumping rates. Such disorder-induced slow-light polaritons provide a platform towards coherent control, collective interactions, and quantum information processing

Compression Behavior of Biodegradable Thermoplastic Plasticizer-Containing Composites

Thermoplastic starch-based composites generate worldwide interest as they are based on green raw materials and undergo complete degradation. The composites were first fabricated from starch and sisal fibers as the major materials via the forming process. The effect of starches with different contents of single- and multicomponent plasticizers on the cushioning properties of the composites was studied. An increase in plasticizer contents within a certain range is shown to enhance materials resistance to pressure and its cushioning performance. With the multicomponent plasticizer content of 15%, the resistance to pressure for four types of composites prepared at different weight ratios of formamide and urea were of the order of 2:1>1:1>1:2, and that of the four types of composites fabricated at different weight ratios of glycerol and ethylene glycol were of the order of 1:2>2:1>1:1. Multicomponent plasticizer-containing starch-based composites are shown to be irregular elastomers and the stress-strain relation to be first defined by a hyperbolic tangent curve function and then by the tangent one.Композиты на основе термопластичного крахмала оказались в центре внимания как отечественных, так и зарубежных ученых, так как они основаны на экологичном сырье и полностью разлагаются. Такие композиты получали формовкой с использованием крахмала и сизалевых волокон в качестве основных материалов. Изучено влияние термопластичного крахмала с различной долей простых и составных пластификаторов на амортизационные свойства композитов. Экспериментальные результаты показали, что в определенных пределах с увеличением содержания пластификаторов повышаются сопротивление материала давлению и его амортизационные характеристики. При содержании составного пластификатора 15% сопротивление давлению четырех типов композитов, полученных с использованием различных массовых соотношений фомамида и мочевины, изменяется в ряду 2:1>1:1>1:2, а с использованием различных массовых соотношений глицерина и этиленгликоля в последовательности 1:2>2:1>1:1. Композиты на основе крахмала, содержащие составной пластификатор, являются нерегулярными эластомерами, и зависимость между напряжением и деформацией описывается в первую очередь функцией гиперболической тангенсоиды и во вторую очередь функцией тангенсоиды.Композити на основі термопластичного крохмалю виявилися в центрі уваги як вітчизняних, так і зарубіжних вчених, так як вони засновані на екологічної сировині і повністю розкладаються. Такі композити отримували формуванням з використанням крохмалю і сизалевих волокон в якості основних матеріалів. Вивчено вплив термопластичного крохмалю з різною часткою простих і складових пластифікаторів на амортизаційні властивості композитів. Експериментальні результати показали, що в певних межах зі збільшенням вмісту пластифікаторів підвищуються опір матеріалу тиску і його амортизаційні властивості. При утриманні складеного пластифікатора 15% опір тиску чотирьох типів композитів, отриманих з використанням різних масових співвідношень фомаміда і сечовини, змінюється в ряду 2: 1> 1: 1> 1: 2, а з використанням різних масових співвідношень гліцерину і етиленгліколю - в послідовності 1 : 2> 2: 1> 1: 1. Композити на основі крохмалю, які містять складовою пластифікатор, є нерегулярними еластомерами, і залежність між напруженням і деформацією описується в першу чергу функцією гіперболічної тангенсоіди і в другу чергу функцією тангенсоіди

Phase Behavior of Bent-Core Molecules

Recently, a new class of smectic liquid crystal phases (SmCP phases) characterized by the spontaneous formation of macroscopic chiral domains from achiral bent-core molecules has been discovered. We have carried out Monte Carlo simulations of a minimal hard spherocylinder dimer model to investigate the role of excluded volume interations in determining the phase behavior of bent-core materials and to probe the molecular origins of polar and chiral symmetry breaking. We present the phase diagram as a function of pressure or density and dimer opening angle $\psi$. With decreasing $\psi$, a transition from a nonpolar to a polar smectic phase is observed near $\psi = 167^{\circ}$, and the nematic phase becomes thermodynamically unstable for $\psi < 135^{\circ}$. No chiral smectic or biaxial nematic phases were found.Comment: 4 pages Revtex, 3 eps figures (included

Optical detection of NMR J-spectra at zero magnetic field

Scalar couplings of the form J I_1 \cdot I_2 between nuclei impart valuable information about molecular structure to nuclear magnetic-resonance spectra. Here we demonstrate direct detection of J-spectra due to both heteronuclear and homonuclear J-coupling in a zero-field environment where the Zeeman interaction is completely absent. We show that characteristic functional groups exhibit distinct spectra with straightforward interpretation for chemical identification. Detection is performed with a microfabricated optical atomic magnetometer, providing high sensitivity to samples of microliter volumes. We obtain 0.1 Hz linewidths and measure scalar-coupling parameters with 4-mHz statistical uncertainty. We anticipate that the technique described here will provide a new modality for high-precision "J spectroscopy" using small samples on microchip devices for multiplexed screening, assaying, and sample identification in chemistry and biomedicine.Comment: 15 pages, 4 Figure

A survey of partial differential equations in geometric design

YesComputer aided geometric design is an area where the improvement of surface generation techniques is an everlasting demand since faster and more accurate geometric models are required. Traditional methods for generating surfaces were initially mainly based upon interpolation algorithms. Recently, partial differential equations (PDE) were introduced as a valuable tool for geometric modelling since they offer a number of features from which these areas can benefit. This work summarises the uses given to PDE surfaces as a surface generation technique togethe