Design charts for contaminant transport through slurry trench cutoff walls

Slurry trench cutoff walls with low-permeability backfill material, such as soil-bentonite and slag-cement-bentonite, are used widely for containment of subsurface pollution. In the design of slurry walls the potential service life for a given thickness or the wall thickness for a target service life are typically determined via analyses of one-dimensional contaminant transport. The difficulty of selecting appropriate inlet and outlet boundary conditions and the mathematical complexity of analytical solutions hinder engineers in undertaking a contaminant transport analysis–based design. Design charts for nondimensionalized effluent flux are presented by developing and using an analytical solution. The methodologies of using these charts in design are demonstrated

Decoupled advection-dispersion method for determining wall thickness of slurry trench cutoff walls

Low-permeability slurry trench cutoff walls are commonly constructed as barriers for containment of subsurface point-source pollution or as part of seepage-control systems on contaminated sites. A method to estimate wall thickness in slurry wall design is proposed based on decoupling the advective and dispersive components of contaminant fluxes through the wall. The relative error of the result obtained by the proposed method compared with that by an analytical solution was found to increase as the ratio of the specified breakthrough exit concentration (c*) to the source concentration (c0) increased. For c*/c0 of less than 0.1, which covers common practical situations, the relative error was not greater than 4% and was always conservative, indicating that the proposed method provides sufficient accuracy for design. For a given breakthrough criterion (i.e., c*/c0), the relative error was low for the scenarios having either a low or high column Peclet number, where either dispersion or advection dominates the contaminant migration, respectively, and the relative error was high for the scenario having an intermediate column Peclet number, in which case the coupling effect of advective and dispersive migrations is relatively high

Pollen Viability, Pistil Receptivity, and Embryo Development in Hybridization of Nelumbo nucifera Gaertn

Seed set is usually low and differs for different crosses of flower lotus (Nelumbo nucifera Gaertn.). The reasons remain unknown, and this has a negative impact on lotus breeding. To determine the causes, we carried out two crosses of flower lotus, that is, “Jinsenianhua” × “Qinhuaihuadeng” and “Qinhuaihuadeng” × “Jinsenianhua” and pollen viability, pistil receptivity, and embryo development were investigated. The pollen grains collected at 05:00-06:00 hrs had the highest viability, and the viabilities of “Jinsenianhua” and “Qinhuaihuadeng” were 20.6 and 15.7%, respectively. At 4 h after artificial pollination, the number of pollen grains germinating on each stigma reached a peak: 63.0 and 17.2 per stigma in “Jinsenianhua” × “Qinhuaihuadeng” and “Qinhuaihuadeng” × “Jinsenianhua”, respectively. At 1 d after artificial pollination, the percentages of normal embryos in the two crosses were 55.0 and 21.9%, respectively; however, at 11 d after pollination, the corresponding percentages were 20.8 and 11.2%. Seed sets of the two crosses were 17.9 and 8.0%, respectively. The results suggested that low pistil receptivity and embryo abortion caused low seed set in “Qinhuaihuadeng” × “Jinsenianhua”, whereas low fecundity of “Jinsenianhua” × “Qinhuaihuadeng” was mainly attributable to embryo abortion

Quantum phase transition in magnetic nanographenes on a lead superconductor

Quantum spins, referred to the spin operator preserved by full SU(2) symmetry in the absence of the magnetic anistropy, have been proposed to host exotic interactions with superconductivity4. However, spin orbit coupling and crystal field splitting normally cause a significant magnetic anisotropy for d/f-shell spins on surfaces6,9, breaking SU(2) symmetry and fabricating the spins with Ising properties10. Recently, magnetic nanographenes have been proven to host intrinsic quantum magnetism due to their negligible spin orbital coupling and crystal field splitting. Here, we fabricate three atomically precise nanographenes with the same magnetic ground state of spin S=1/2 on Pb(111) through engineering sublattice imbalance in graphene honeycomb lattice. Scanning tunneling spectroscopy reveals the coexistence of magnetic bound states and Kondo screening in such hybridized system. Through engineering the magnetic exchange strength between the unpaired spin in nanographenes and cooper pairs, quantum phase transition from the singlet to the doublet state has been observed, in consistent with quantum models of spins on superconductors. Our work demonstrates delocalized graphene magnetism host highly tunable magnetic bound states with cooper pairs, which can be further developed to study the Majorana bound states and other rich quantum physics of low-dimensional quantum spins on superconductors.Comment: 13 pages, 4figure

Evasion of anti-growth signaling: a key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally-occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally-occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting

The hornwort genome and early land plant evolution

Hornworts, liverworts and mosses are three early diverging clades of land plants, and together comprise the bryophytes. Here, we report the draft genome sequence of the hornwort Anthoceros angustus. Phylogenomic inferences confirm the monophyly of bryophytes, with hornworts sister to liverworts and mosses. The simple morphology of hornworts correlates with low genetic redundancy in plant body plan, while the basic transcriptional regulation toolkit for plant development has already been established in this early land plant lineage. Although the Anthoceros genome is small and characterized by minimal redundancy, expansions are observed in gene families related to RNA editing, UV protection and desiccation tolerance. The genome of A. angustus bears the signatures of horizontally transferred genes from bacteria and fungi, in particular of genes operating in stress-response and metabolic pathways. Our study provides insight into the unique features of hornworts and their molecular adaptations to live on land

Engineered Biomaterials to Enhance Stem Cell-Based Cardiac Tissue Engineering and Therapy

Cardiovascular disease is a leading cause of death worldwide. Since adult cardiac cells are limited in their proliferation, cardiac tissue with dead or damaged cardiac cells downstream of the occluded vessel does not regenerate after myocardial infarction. The cardiac tissue is then replaced with nonfunctional fibrotic scar tissue rather than new cardiac cells, which leaves the heart weak. The limited proliferation ability of host cardiac cells has motivated investigators to research the potential cardiac regenerative ability of stem cells. Considerable progress has been made in this endeavor. However, the optimum type of stem cells along with the most suitable matrix-material and cellular microenvironmental cues are yet to be identified or agreed upon. This review presents an overview of various types of biofunctional materials and biomaterial matrices, which in combination with stem cells, have shown promises for cardiac tissue replacement and reinforcement. Engineered biomaterials also have applications in cardiac tissue engineering, in which tissue constructs are developed in vitro by combining stem cells and biomaterial scaffolds for drug screening or eventual implantation. This review highlights the benefits of using biomaterials in conjunction with stem cells to repair damaged myocardium and give a brief description of the properties of these biomaterials that make them such valuable tools to the field.Anwarul Hasan acknowledges the startup grant and the University Research Board (URB) grant from American University of Beirut, Lebanon, and the National Council for Scientific Research (CNRS) grant, Lebanon, as well as the Farouk Jabre interdisciplinary research award. Arghya Paul acknowledges the University of Kansas New Faculty General Research Fund for support and assistance with this work. The authors also acknowledge an investigator grant provided by the Institutional Development Award (IDeA) from the National Institute of General Medical Sciences (NIGMS) of the NIH Award Number P20GM103638-04 (to A.P.). R.W. acknowledges the financial support from NIGMS (NIH, T32-GM008359) Biotechnology Predoctoral Research Training Program

Investigation of the refractive status of preschool children in Xiantao, Hubei Province

AIM: To investigate the refractive status of the preschool children in Xiantao, Hubei Province in order to find out the abnormal refraction error beyond the physiological range. <p>METHODS: In this cross-sectional study, we investigated preschool children in kindergartens and the scattered ones were 12 716(25 432 eyes)ranging from 6mo～6 years old. 1 581 children(3 162 eyes)were diagnosed ametropia by Suresight refractive screening instrument, which were confirmed again after mydriasis optometry. <p>RESULTS: The incidence rate of ametropia in preschool children in Xiantao was 12.4%, and statistics showed no significant difference between boys and girls(<i>P</i>>0.05), but had differences of morbility rate among each age group(<i>P</i><0.05). With age increasing morbility rate of the refractive error decreased. The simple hyperopia and the compound hyperopia astigmatism were dominant in all refraction error. Professional ophthalmologists diagnosed amblyopia in 261 children(522 eyes), which was 16.5%, among 1 581 abnormal refractive children(3 162 eyes)screened out by Suresight refractive screening instrument. <p>CONCLUSION: The incidence rate of ametropia decreases with age increasing in the preschool children from 6mo～6 years old, which imply preschool children should have mydriasis optometry in order to find out amblyopia and other congenital eye disease

A Fluidic Birefringent Sensor for Concentration Measurements of Chemical Solutions in Homodyne Interferometer

We have fabricated and tested, to the best of our knowledge, the first fluidic birefringent sensor (FBS) for the concentration measurements of chemical solutions in a homodyne interferometer. The performance of KTP (potassium titanyl phosphate)-based FBS has been experimentally evaluated for successful concentration measurements in salt and hydrochloric acid solutions. The measurement resolution is 0.0088 wt. % in the concentration range of 2.5 wt. % for hydrochloric acid solution. According to the experimental results, the chemical resistance property gives the KTP sensor the potential to be used in harsh environments