This paper uses approximate analytical formulas and numerical results with the bino-dominated dark matter (DM) as an example to analyze the impact of the LUX-ZEPLIN (LZ) experiment on the DM ...phenomenology and naturalness in the Minimal Supersymmetric Standard Model (MSSM). We conclude that the limitation of the latest LZ experiment worsens the naturalness of the MSSM, as the predictions of the Z-boson mass and DM relic density demonstrate, particularly in the regions where the correct DM relic density is obtained by the Z- or h-mediated resonant annihilations.
Based on the influence of moisture content, dry density and temperature (less than over equal to 0°C) on the thermal conductivity of lime-modified red clay, the thermal conductivity was measured by ...transient hot wire method. A total of 125 data were obtained and the evolution law of thermal conductivity with influencing factors was analyzed. The fitting formula of thermal conductivity of lime-modified red clay and a variety of intelligent prediction models were established and compared with previous empirical formulas. The results show that the thermal conductivity of lime-modified red clay increases linearly with water content and dry density. The change of thermal conductivity with temperature is divided into three stages. In the first stage, the thermal conductivity increases slowly with the decrease of temperature in the temperature range of-2°Cto 0°C. In the second stage, in the temperature range of-5°Cto (-2)°C, the thermal conductivity increases rapidly with the decrease of temperature. In the third stage, in the range of-10°Cto (-5)°C, the thermal conductivity changes little with the decrease of temperature, and the fitting curve tends to be stable. The fitting formula model and various intelligent prediction models can realize the accurate prediction of the thermal conductivity of lime-improved soil. Using RMSE (Root Mean Square Error) and MAPE (Mean Absolute Percentage Error) to evaluate the model, it is found that the GBDT decision tree model has the best prediction effect, the RMSE value of the predicted value is 0.084, and the MAPE value is 4.1%. The previous empirical models have poor prediction effect on the thermal conductivity of improved red clay. The intelligent prediction models such as GBDT decision tree with strong universality and high prediction accuracy are recommended to predict the thermal conductivity of soil.
Lead-zinc smelting slag (LZSS) is a hazardous waste due to the presence of heavy metals (Pb, Zn, Cu and Cr) and its improper disposal has serious consequences on ecosystem. The ...solidification/stabilization of hazardous waste through geopolymer binders is a promising technique to overcome these consequences. Hence, LZSS was solidified through composite based geopolymer (Pulverized Fuel Ash (PFA) and Blast Furnace Slag (BFS)). The experiment was carried out in to two steps i.e. strength development and solidification. Effect of various factors on compressive strength was evaluated through single-factor and orthogonal experiments. While, solidification/stabilization efficiency of composite based geopolymer was analyzed through compressive strength and leaching concentration of heavy metals in two extractants. The results showed that highest compressive strength (47.39 MPa) was achieved through optimization of each factor. The LZSS was solidified in composite based geopolymer sample having highest compressive strength. While, the compressive strength was decreased to 15 MPa with 80% addition of LZSS. According to leaching tests, this strength was satisfactory for landfill disposal and construction purposes because Pb, Zn, Cu and Cr had not exceeded the critical limits. The heavy metals were solidified through physical and chemical means which was proved by X-ray diffraction (XRD) analysis, Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrometry (FTIR) analysis.
•The feasibility study of geopolymer with high strength based on uncalcined coal gangue and blast furnace slag was conducted.•Response surface method was adopted for the optimization of preparation ...of composite geopolymer.•The effective solidification of heavy metals in lead-zinc tailing were achieved.•Solidified bodies have potential for application of construction purpose.
The improper disposal of solid wastes could bring great pressures and threats to ecosystem. These detrimental impacts could be reduced or eliminated through solidification/stabilisation technology based on geopolymer. In this paper, composite based geopolymer prepared from coal gangue and blast furnace slag was used for the solidification of heavy metals in lead–zinc tailing (LZT). The impact of various factors on compressive strength development in composite geopolymer was evaluated through response surface experiment. Additionally, the sample with maximum strength (91.13 MPa) was chosen to solidify LZT. The results showed that strength of solidified bodies with addition of 70% LZT fell to 21.68 MPa. Based on leaching tests, these samples could potentially be used for construct applications, since leaching concentrations were far below the standard limits. Heavy metals in LZT were effectively solidified via physical and chemical ways, which was evidenced by chemical speciation analysis, mercury intrusion porosimetry, X-ray diffraction and scanning electron microscope with energy dispersive spectrometry analyses.
We examine the parameter space of the constrained MSSM by considering various experimental constraints. For the dark matter sector, we require the neutralino dark matter to account for the relic ...density measured by the WMAP and satisfy the XENON limits on its scattering rate with the nucleon. For the collider constraints, we consider all relevant direct and indirect limits from LEP, Tevatron and LHC as well as the muon anomalous magnetic moment. Especially, for the limits from Bs→μ+μ−, we either directly consider its branching ratio with the latest LHC data or alternatively consider the double ratio of the purely leptonic decays defined by Br(Bs→μ+μ−)/Br(Bμ→τντ)Br(Ds→τντ)/Br(D→τμτ). We find that under these constraints, the mass of the lightest Higgs boson (h) in both the CMSSM and the NUHM2 is upper bounded by about 124 GeV (126 GeV) before (after) considering its theoretical uncertainty. We also find that for these models the di-photon Higgs signal at the LHC is suppressed relative to the SM prediction, and that the lower bound of the top-squark mass goes up with mh, reaching 600 GeV for mh=124 GeV.
Cell-fate decisions remain poorly understood at the chromatin level. Here, we map chromatin remodeling dynamics during induction of pluripotent stem cells. ATAC-seq profiling of MEFs expressing ...Oct4-Sox2-Klf4 (OSK) reveals dynamic changes in chromatin states shifting from open to closed (OC) and closed to open (CO), with an initial burst of OC and an ending surge of CO. The OC loci are largely composed of genes associated with a somatic fate, while the CO loci are associated with pluripotency. Factors/conditions known to impede reprogramming prevent OSK-driven OC and skew OC-CO dynamics. While the CO loci are enriched for OSK motifs, the OC loci are not, suggesting alternative mechanisms for chromatin closing. Sap30, a Sin3A corepressor complex component, is required for the OC shift and facilitates reduced H3K27ac deposition at OC loci. These results reveal a chromatin accessibility logic during reprogramming that may apply to other cell-fate decisions.
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•ATAC-seq reveals chromatin accessibility dynamics during reprogramming•TFs associated with initial chromatin closing are barriers for reprogramming•OSK opens the pluripotent loci gradually through a direct process•OSK closes the somatic loci indirectly in part through SAP30
Li et al. show that Yamanaka factors remodel the nuclear architecture of MEFs following a binary logic that may guide further improvement in reprograming technology and be applicable for other cell-fate decisions.
This review outlines classic and current research, scientific documents and research achievements in bioleaching, particularly in respect of the bioleaching of chalcopyrite and pyrite. The diversity ...and commonality of the microbial leaching process can be easily studied through comparing the bioleaching mechanism and the application of these two metal sulfides. The crystal, electronic and surface structures of chalcopyrite and pyrite are summarized in detail in this paper. It determines the specific and complicated interaction pathways, kinetics of the atmospheric/aqueous oxidation, and the control process of bioleaching of the minerals as the precondition. Bioleaching of metal sulfides is performed by a diverse group of microorganisms and microbial communities. The species of the bacteria which have a significant effect on leaching ores are miraculously diverse. The newly identified acidophilic microorganisms with unique characteristics for efficient bioleaching of sulfidic minerals are increasing sharply. The cell-to-cell communication mechanisms, which are still implicit, elusive and intangible at present day, have gradually become a research hotspot. The different mineralogy characteristics and the acid solubility of the metal sulfides (e.g., chalcopyrite and pyrite) cause two different dissolution pathways, the thiosulfate and the polysulfide pathways. The bioleaching mechanisms are categorized by contact (an electrostatic attachment) and noncontact (planktonic) process, with emphasis on the produce of extracellular polymeric substances and formation of biofilm on the surface of the metal sulfides in this paper. The division of the direct and indirect effect are not adopted due to the redox chain, the reduction of the ferric iron and oxidation of the ferrous iron. The molecular oxygen is reduced by the electrons extracted from the specific metal sulfide, via a redox chain forming a supercomplex spanning the periplasmic space and connecting both outer and inner membrane. The passivation of the mineral surface can obviously hinder the dissolution of metal sulfides during the bioleaching process, which is significantly affected by the kinetic model, microenvironment on the surface of ore and the leach conditions, such as temperature, pH and E
. The new development of mechanism research, enhanced and intensified technologies on the bioleaching of chalcopyrite and pyrite, are conducted and summarized from the different branches of natural science. Some are depicted and explained based on molecular level in this paper. Catalyst and catalytic mechanisms in bioleaching and biooxidation for this two sulfide minerals have been concluded and applied for several decades, the continuous emergence of the new material and technology are also gradually applied into the biohydrometallurgy. The industrial applications of the bioleaching on chalcopyrite and pyrite are totally based on the understanding of the interaction mechanism between microbes and minerals, the optimization of ore leaching conditions and the development of new material and the leaching equipment. It is not incredible and unimaginable to take a different bioleaching process and diagram to deal with the two sulfuric metals, which is vital to succeed in elevating the leaching rate of copper.
Glycosylation reaction involving the coupling of a glycosyl donor with a glycosyl acceptor is one of the cornerstones of chemical preparation of pure glycans and glycoconjugates of biological ...relevance. Catalytic glycosylation of glycosyl ester donors and thioglycosides is an attractive but underexplored topic in carbohydrate chemistry. Herein, triflic imide (Tf2NH)‐catalyzed glycosylation of various O‐, S‐, and C‐nucleophiles has been achieved using disarmed glycosyl ortho‐isopropenylphenylacetates (GIPPAs) and ortho‐isopropenylbenzyl thioglycosides as glycosylating agents. The reactions proceed under mild conditions to give the desired glycosides in good‐to‐excellent yields. Of particular note, the comparable reactivity for the α‐isomers and the β‐ones of GIPPAs is observed. The mechanistic investigation demonstrates that the isopropenyl group is essential for the reaction and its preferential protonation triggers the reaction. This work provides another member to the arsenals of glycosyl ester and thioglycoside donors suitable for acid‐catalyzed glycosylation to create various glycosidic bonds.
An efficient protocol for Tf2NH‐catalyzed glycosylation of disarmed glycosyl ortho‐isopropenylphenylacetates and ortho‐isopropenylbenzyl thioglycosides has been established. Mechanistically, the reaction involves the preferential protonation of the isopropenyl group, the generation of reactive glycosylating species by the cation‐triggering intramolecular cyclization, and the ensuing glycosylation event.
Preferential CO oxidation (PROX) was investigated by using dealloyed nanoporous gold (NPG) catalyst under ambient conditions. Systematic investigations were carried out to characterize its catalytic ...performance by varying reaction parameters such as temperature and co-existence of CO2 and H2O, which revealed that NPG was a highly active and selective catalyst for PROX, especially at low temperature. At 20°C, the exit CO concentration could be reduced to less than 2 ppm with a turnover frequency of 4.1 × 10(-2) s(-1) at a space velocity of 120,000 mL h(-1) g(-1)cat. and its high activity could retain for more than 24 hours. The presence of residual Ag species in the structure did not seem to improve the intrinsic activity of NPG for PROX; however, they contributed to the stabilization of the NPG structure and apparent catalytic activity. These results indicated that NPG might be readily applicable for hydrogen purification in fuel cell applications.
Planting spacing plays a key role in the root system architecture of the cotton group under local irrigation. This study used the Cellular Automata (CA) theory to establish a root visualization model ...for the cotton group at two different planting spacing (30 and 15 cm) within a leaching-pond. At a planting spacing of 30 cm, the lateral roots grew almost horizontally toward the irrigation point, and a logarithmic relationship was observed between root length density and soil water suction. However, at a planting spacing of 15 cm, the lateral roots exhibited overlapping growth and mainly competed for resources, and a power function relationship was observed between root length density and soil water suction. The main parameters of the visualization model for each treatment were essentially consistent with the experimental observations, with respective simulation errors were 6.03 and 15.04%. The findings suggest that the correlation between root length density and soil water suction in the cotton plants is a crucial driving force for the model, leading to a more accurate replication of the root structure development pathway. In conclusion, the root system exhibits a certain degree of self-similarity, which extends into the soil.
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