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In this paper, we formed two BC2P/MoS2 van der Waals (vdW) heterostructures, namely BC2P/MoS2-a and -b heterostructures by stacking the MoS2 and BC2P monolayers. First, by analyzing binding energies, flat average differential charge density and elastic constants of two vdW heterostructures, their structures and formation possibility were studied. Two vdW heterostructures are semiconductors with their indirect band gaps as 0.774/1.405 eV and 1.028/1.458 (direct) eV under the GGA-PBE/HSE06 functional, respectively. Moreover, they are two-dimensional materials with close hardness to the graphene. Especially, two vdW heterostructures possess very high absorption coefficients (> 30%) and low reflection coefficients (< 4%) for the visible light, which makes them as novel and potential two-dimensional materials in the application of optoelectronic, electronic and photovoltaics devices. [ABSTRACT FROM AUTHOR]

C18H21NO8S, monoclinic, P121/c1 (no. 14), a = 21.069(5) Å, b = 11.494(3)Å, c = 7.996(2)Å, β = 97.257(3)°, V = 1920.9Å3, Z = 4, Rgt(F) = 0.044, wRref(F2) = 0.124, T = 298 K.

The elastic and structural properties of nanolaminate Zr2InC are studied by first-principles, and it is shown that, for any used modes, including the generalized gradient approximation (GGA) and localized density approximation, there always exists an ultraincompressibility along c axis between 70 GPa and 400 GPa. Such anomalous behavior is originated from the slowdown of core-valence charge transfer. The rapid shift of Zr atom along c axis also contributed much to the ultraincompressibility as it is greatly reduced once the Zr atom shift suspends along c axis above about 400 GPa. Both the elastic constants and the phononic vibrational frequencies investigations confirmed the structural unstable simultaneously. The Poisson's ratio investigations observed a higher ionic or weaker covalent contribution in interatomic bonding and the degree of ionicity increases with pressure. [ABSTRACT FROM AUTHOR]

Considered in this paper is an inverse Robin problem governed by a steady-state diffusion equation. By the Robin inverse problem, one wants to recover the unknown Robin coefficient on an inaccessible boundary from Cauchy data measured on the accessible boundary. In this paper, instead of reconstructing the Robin coefficient directly, we compute first the Cauchy data on the inaccessible boundary which is a linear inverse problem, and then compute the Robin coefficient through Newton's law. For the Cauchy problem, a parameter-dependent coupled complex boundary method (CCBM) is applied. The CCBM has its own merits, and this is particularly true when it is applied to the Cauchy problem. With the introduction of a positive parameter, we can prove the regularized solution is uniformly bounded with respect to the regularization parameter which is a very good property because the solution can now be reconstructed for a rather small value of the regularization parameter. For the problem of computing the Robin coefficient from the recovered Cauchy data, a least square output Tikhonov regularization method is applied to Newton's law to obtain a stable approximate Robin coefficient. Numerical results are given to show the feasibility and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

OBJECTIVE: DJ-1 is a negative regulator of PTEN and plays a role in tumorigenesis. Abnormal miR-203 expression is associated with pancreatic cancer. Bioinformatics analysis showed a targeted relationship between miR-203 and DJ-1 3'-UTR. This study investigated whether miR-203 regulates DJ-1 expression and its role in pancreatic cancer cell proliferation, apoptosis, and cisplatin (DDP) resistance. MATERIALS AND METHODS: The Dual-Luciferase reporter gene assay validated the targeted regulation between miR-203 and DJ-1. The DDP-resistant cell line SW1990/DDP was established and divided into miR-NC group and miR- 203 mimic group followed by analysis of the expression of DJ-1, PTEN and p-AKT, cell apoptosis, and proliferation. RESULTS: There was a targeted relationship between miR-203 and DJ-1 mRNA. The expression of miR-203 in SW1990/DDP cells was significantly lower than that in SW1990 cells, while the expression of DJ-1 mRNA and protein was significantly higher than that in SW1990 cells. Compared with miR-NC group, the expression of DJ-1 and p-AKT protein in SW1990/DDP cells was significantly decreased in miR-203 mimic transfection group, while the expression of PTEN was significantly increased with increased cell apoptosis and decreased cell proliferation, as well as reduced DDP resistance. CONCLUSIONS: The decreased expression of miR-203 and the increased expression of DJ-1 is associated with drug resistance in pancreatic cancer cells. Elevated miR-203 can inhibit the expression of DJ-1, affect the activity of PTEN-PI3K/AKT pathway, inhibit the proliferation of pancreatic cancer cells, induce cell apoptosis, and reduce DDP resistance of pancreatic cancer cells. [ABSTRACT FROM AUTHOR]

Bioluminescence tomography (BLT) aims at the determination of the distribution of a bioluminescent source quantitatively. The mathematical problem involved is an inverse source problem and is ill-posed. With the Tikhonov regularization, an optimization problem is formed for the light source reconstruction and it is usually solved by gradient-type methods. However, such iterative methods are often locally convergent and thus the solution accuracy depends largely on initial guesses. In this paper, we reformulate the reduced regularized optimal problem as a nonlinear equation and apply a homotopy method, which is a powerful tool for solving nonlinear problem due to its globally convergent property, to it. Numerical experiments show that the application of the homotopy technique is feasible and can produce satisfactory approximate solutions for a very large range of initial guesses. [ABSTRACT FROM PUBLISHER]

Abstract: Since February 2012, CO2, H2O, and wind data at 10 Hz have been measured by the open‐path eddy covariance systems at 8, 16, 47, 80, 140, 200, and 280 m above ground level on the 325 m Beijing meteorological tower. Analysis of the data from 2013 to 2016 indicates that the annual averaged CO2 concentration increased and the local and regional CO2 emission decreased with the sequestration of background CO2 concentration. The maximum values occurred during winter, and the minimum values occurred during summer. During spring, summer, and autumn, there was a constant CO2 flux layer from 47 m to 140 m. However, during winter, CO2 flux increased with height, and the maximum appeared at approximately 140 m and then decreased with height. Above 47 m, the CO2 fluxes were represented as the net efflux, and below 16 m, the fluxes were near zero or a net uptake. At all observed heights, the diurnal variation in the CO2 concentration displayed a clear cycle with a peak corresponding to the morning transportation rush hour. The local wavelet power spectra of the CO2 concentration, CO2 flux, and other meteorological elements identified significant cross‐wavelet powers near the 24 h and 365 day bands for the CO2 concentration and flux with temperature, wind speed, friction velocity, and turbulent kinetic energy. [ABSTRACT FROM AUTHOR]

Considered in this paper is a Cauchy problem governed by an elliptic partial differential equation. In the Cauchy problem, one wants to recover the unknown Neumann and Dirichlet data on a part of the boundary from the measured Neumann and Dirichlet data, usually contaminated with noise, on the remaining part of the boundary. The Cauchy problem is an inverse problem with severe ill-posedness. In this paper, a coupled complex boundary method (CCBM), originally proposed in [Cheng XL, Gong RF, Han W, et al. A novel coupled complex boundary method for solving inverse source problems. Inverse Prob. 2014;30:055002], is applied to solve the Cauchy problem stably. With the CCBM, all the data, including the known and unknown ones on the boundary are used in a complex Robin boundary on the whole boundary. As a result, the Cauchy problem is transferred into a complex Robin boundary problem of finding the unknown data such that the imaginary part of the solution equals zero in the domain. Then the Tikhonov regularization is applied to the resulting new formulation. Some theoretical analysis is performed on the CCBM-based Tikhonov regularization framework. Moreover, through the adjoint technique, a simple solver is proposed to compute the regularized solution. The finite-element method is used for the discretization. Numerical results are given to show the feasibility and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To study the expression profile and role of microRNA miR-34a in Leukemia stem cells (LSC) and during its metastasis. We examined upon the enforced expression of miR-34a in TIM3 positive leukemia stem cells and study the impact of leukemia stem cells and its metastasis. PATIENTS AND METHODS: Samples were collected from acute myeloid leukemia (AML) children along with controls. Immunohistochemistry analysis was performed with TIM3 antibody followed by Sorting of TIM3 positive cells by flow cytometry and the expression level of miR-34a was quantified by qRT-PCR assay. RESULTS: Immunohistochemistry in accordance with Sorting of TIM3 positive cells by flow cytometry concludes that the leukemia stem cells (LSC) were present in the samples. Induced expression of miR-34a in TIM3 positive leukemia stem cells (LSC), inhibits the clonogenic expansion, tumor progression and metastasis of leukemia. CONCLUSIONS: The enforced expression of miR-34a in TIM3 positive leukemia stem cells inhibits the leukemia stem cells and its metastasis. Our study illustrates that miR-34a is a key regulator and which will be developed as a novel therapeutic agent against leukemia stem cells (LSC). [ABSTRACT FROM AUTHOR]

In this paper, we propose a new method to extract the extreme fluctuations of vertical velocity in the unstable atmospheric surface layer. Unlike the commonly used conditional sampling analysis, this method defines a threshold by using a systematical method and tries to reduce the artificiality in this process. It defines threshold as the position where the types of probability density functions (PDFs) of vertical velocity fluctuations begin to change character from stable distributions to truncated stable distributions. Absolute values of fluctuations greater than the threshold are considered to be extreme fluctuations. We then analyze the statistical characteristics of extracted extreme fluctuations of vertical velocity. Our results show that the amplitudes of extreme fluctuations are exponentially distributed, and the waiting times between extreme fluctuations have stretched exponential distributions. It suggests that there are statistical correlations in the time series of vertical velocity because independent time series can only have exponentially distributed waiting times. The durations of extreme fluctuations are also found to be stretched exponential distributed, while for the independent time series the distributions of durations are delta-like. Finally, the PDFs of amplitudes, waiting times and durations are all well parameterized in the context of Monin-Obukhov theory. [ABSTRACT FROM AUTHOR]

The superplastic behaviour of an ultrahigh strength steel (Fe-0·47C-1·98Mn-1·37Si-0·91Cr-0·25Mo) after a proper predeformation has been studied. The predeformation mentioned above was conducted with true strain of 1·2 at strain rate of 10−3 s−1 at 973 K. It was found that water cooled specimen after the predeformation exhibits superplastic characteristics under suitable conditions although the microstructure of the specimen contains massive martensite, which is commonly thought to be unbeneficial for superplasticity. Further study shows that the microstructure transforms to ferrite+spheroidised carbide dual phase under a very small strain during the early stage of superplastic deformation. [ABSTRACT FROM AUTHOR]

Biomedical imaging has developed into the level of molecular imaging. Bioluminescence tomography (BLT), as an optical imaging modality, is a rapidly developing new and promising field. So far, much of the theoretical analysis of BLT is based on a diffusion approximation equation for media with constant refractive index. In this article, we study the BLT problem for media with spatially varying refractive index. We introduce a general framework with Tikhonov regularization for this purpose, present its well-posedness and establish the error bounds for its numerical solution by the finite element method. Numerical results are reported on simulations of the BLT problem for media with spatially varying refractive index. [ABSTRACT FROM AUTHOR]

Erbium and silicon were dual implanted into thermally grown SiO2 film on Si (110) substrates, followed by thermal treatment at 700-1200 °C for 30 min. The microstructure was studied by transmission electron microscope and x-ray diffraction. When the implanted films were annealed at T > 900 °C, the silicon nanocrystals (nc-Si) enwrapped by amorphous silicon (a-Si) could be observed. The thermal quenching behavior at λ = 1.535 µm and its relation with the annealling temperature were also investigated. With increasing annealing temperature, the portion of a-Si and the thermal quenching both decreased. Efficient luminescence from Er ions and weak intensity thermal quenching were obtained from the sample annealed at 1100 °C. The role of a-Si in non-radiative processes at T > 100 K is discussed. [ABSTRACT FROM AUTHOR]

Bacterial mercury oxidation coupled to denitrification offers great potential for simultaneous removal of elemental mercury (Hg 0 ) and nitric oxide (NO) in a denitrifying membrane biofilm reactor (MBfR). Four potentially contributory mechanisms tested separately, namely, membrane gas separation, medium absorption, biosorption and biotransformation, which contributed 4.9%/7.2%, 8.1%/8.9%, 38.8%/9.5% and 48.2%/84.9% of overall Hg 0 /NO removal in MBfR. Herein, Hg 0 bio-oxidation, oxidative Hg 0 biosorption and denitrification played leading roles in simultaneous removal of Hg 0 and NO. Living microbes performed simultaneous Hg 0 bio-oxidation and denitrification, in which Hg 0 as electron donor was biologically oxidized to oxidized mercury (Hg 2+ ), while NO as the terminal electron acceptor was denitrified to N 2 . The Hg 2+ further complexed with humic acids in extracellular polymeric substances via functional groups (-SH, -OH, -NH - and -COO - ) and formed humic acids bound mercury (HA-Hg). Non-living microbial matrix performed oxidative Hg 0 biosorption, in which Hg 0 may be physically adsorbed by cellular matrix, then non-metabolically oxidized to Hg 2+ via oxidative complexation with -SH in humic acids and finally cleavage of S-H bond and surface charge transfer led to formation of HA-Hg. Therefore, bioconversion of Hg 0 to HA-Hg by Hg 0 bio-oxidation and oxidative Hg 0 biosorption coupled with NO denitrification to N 2 dynamically cooperated to accomplish simultaneous removal of Hg 0 and NO in MBfR., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Photocatalytic membrane coupled to biodegradation offers potential for degrading volatile organic compounds (VOCs) in photocatalytic membrane biofilm reactor. An intimately coupled photocatalysis and biodegradation reactor was operated in continuous operation for 500 days to treat simulated waste gas containing toluene. Toluene removal efficiency obtained 99%, with the elimination capacity of 550 g m -3 ·h -1 . Membrane photocatalysis coupled to biodegradation was created to improve toluene removal from 11 to 20%. The dominant genera were Lysinibacillus, Hydrogenophaga, Pseudomonas at 30 d, Rudaea, Dongia, Litorilinea at 230 d xyl, Tod, Tcb, Bed, Tmo, Tbu, Tou, Dmp, Cat were functional genes of toluene metabolism, as shown by16S rDNA and metagenomic sequencing. Photocatalysis destroyed part of the toluene into biodegradable intermediates that were immediately mineralized by microorganisms in biofilm, some toluene was directly degraded by toluene degrading bacterial community into carbon dioxide and water. The novel hybrid photocatalytic membrane biofilm reactor is a cost-effective and robust alternative to VOCs treatment., (Copyright © 2019. Published by Elsevier Inc.)

Objectives: Alzheimer's disease is an age-related neurodegenerative disease and a synaptic function defect disease, the clinical symptoms are mainly progressive cognitive impairment, affecting patient's social function. Aim of this report was to investigate the effect of topiramate on apoptosis-related protein expression (Bcl-2, Survivin, Fas, Bax and Caspase-3) in the hippocampus of a rat model with Alzheimers Disease (AD)., Materials and Methods: Thirty-six adult Wistar rats were randomly divided into a control group, a model group and a test group. A dose of amyloid beta-protein 1-40 (Aβ1-40) was injected into the hippocampus of the rats in the model and test groups, and the control rats are injected with same amount of saline. After AD model was successfully established, the rats in each group were administrated with an i.p. injection of topiramate (20 mg/kg/d) for 30 days. The effect of topiramate on the apoptosis-related protein levels in hippocampus neurons was studied by immunohistochemistry., Results: The number of Bcl-2 and Survivin positive cells and optical density in hippocampus of rats in test group was more than those of rats in model groups, but less than those of rats in control group (p < 0.01); Fas, Bax and Caspase-3 positive cells and optical density in hippocampus of rats in test group was less than those of rats in the model group, but more than those of rats in control group (p < 0.01)., Conclusions: Alzheimer's disease can induce apoptosis of hippocampus neurons in rats. Topiramate can prevent apoptosis of hippocampus neurons, at least in part, by increasing expression of Bcl-2 and Survivin and decreasing expression of Fas, Bax and Caspase-3.

Objectives: To explore the effect of edaravone (ED) on apoptosis of hippocampus neurons in seizures rats induced by pentylenetetrazole (PTZ)., Materials and Methods: Forty-eight adult Wistar rats were randomly divided into normal control (NC) group, PTZ group, and ED group. A dose of PTZ [35 mg/(kg·day)] was intraperitoneally (i.p.) injected into the rats of PTZ group and ED group until the kindling criterion was reached. After kindling, the rats of ED group were administered i.p. with ED [0.8 mg/(kg·day)]; the rats of PTZ group were administered i.p. with normal saline. After 30 min, seizures were induced by administering PTZ i.p. The influence of ED on Fas, Caspase-3, and Survivin protein immunoreactivity on hippocampus neurons was studied by immunohistochemistry method., Results: Fas and Caspase-3 positive cells and optical density in hippocampus in PTZ group were more than that of ED group and NC group (all p < 0.01), but Survivin-positive cells and optical density in hippocampus in PTZ group were less than that of ED group (p < 0.01) and were more than that of NC group (p < 0.05); Fas- and Caspase-3-positive cells and optical density in hippocampus in ED group were more than that of NC group (all p < 0.05), but Survivin-positive cells and optical density in hippocampus in ED group were more than that of NC group (p < 0.01)., Conclusions: Seizure can induce apoptosis of hippocampus neurons on seizures rats, but ED can resist the apoptosis of hippocampus neurons by increased expression of Survivin and decreased expression of Fas and Caspase-3.

Receptor-based comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were performed on a series of 54 progesterone receptor (PR) inhibitors. The established CoMFA model from the training set gives statistically significant results with the cross-validated q (2) of 0.534 and non-cross-validated [Formula: see text] of 0.947. The best CoMSIA model was derived by the combination of steric field and hydrophobic field with a q (2) of 0.615 and [Formula: see text] of 0.954. A test set of 18 compounds was used to validate the predictive ability of the two models. The predicted correlation coefficients [Formula: see text] are 0.681 and 0.677 for CoMFA and CoMSIA models, respectively. Based on the CoMFA maps, the key structural characters of progesterone receptor inhibitors are identified. Moreover, the binding modes of oxindoles and benzimidazol-2-ones are also given by the quantum mechanical/molecular mechanical (QM/MM) calculations. This may provide useful information for drug design.

Although smoking-related coronary vascular disease is well documented, the effects of nicotine have not been fully investigated. There is controversy over reports about the effect of nicotine on apoptosis. The effect of nicotine on apoptosis of human umbilical vein endothelial cells (HUVECs) and the expressions of Fas/Fas ligand (FasL) and caspase-3 were evaluated in this study. Annexin V fluorescein isothiocyanate and propidium iodide double staining demonstrated that nicotine (0.2 microM, 0.5 microM and 1 microM) could induce apoptosis of HUVECs; reverse transcription (RT)-PCR and Western blotting analysis demonstrated that levels of Fas and FasL expression were increased in nicotine-treated HUVECs. Moreover, caspase-3 expression was also increased. These data indicate that nicotine induces the apoptosis of HUVECs, and that the Fas/FasL pathway may play an important role. This provides evidence that nicotine may have an important role in cardiovascular pathology and atherogenesis., (Copyright 2010 Prous Science, S.A.U. or its licensors. All rights reserved.)

The reaction mechanisms of two inhibitor TFK(+) and TFK(0) binding to H447I mutant mouse acetylcholinesterase (mAChE) have been investigated by using a combined ab initio quantum mechanical/molecular mechanical (QM/MM) approach and classical molecular dynamics (MD) simulations. TFK(+) binding to the H447I mutant may proceed with a different reaction mechanism from the wild-type. A water molecule takes over the role of His447 and participates in the bond breaking and forming as a "charge relayer". Unlike in the wild-type mAChE case, Glu334, a conserved residue from the catalytic triad, acts as a catalytic base in the reaction. The calculated energy barrier for this reaction is about 8kcal/mol. These predictions await experimental verification. In the case of the neutral ligand TFK(0), however, multiple MD simulations on the TFK(0)/H447I complex reveal that none of the water molecules can be retained in the active site as a "catalytic" water. Taken together our computational studies confirm that TFK(0) is almost inactive in the H447I mutant, and also provide detailed mechanistic insights into the experimental observations.