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N80 steel and 3Cr13 steel used as tubing and hydraulic anchors are inevitably coupled in the CO2 flood oil well, which is prone to galvanic corrosion. Hence, the corrosion rate test and galvanic corrosion test of N80 steel and 3Cr13 steel under CO2 environment were carried out, for clarifying the galvanic corrosion laws of the two steels under the action of various factors including CO2 content, temperature, pressure and salinity. Results showed that the galvanic corrosion occurred at the two steels in CO2 flooding oil wells. 3Cr13 steel was the cathode, which was not affected by galvanic corrosion. In contrast, N80 steel was the anode, and its galvanic corrosion rate increased, which exhibited the same trend as the conventional corrosion, namely increasing with the increase of CO2 content, temperature, pressure and salinity. In addition, the galvanic corrosion sensitivity factor decreased with the increase of CO2 content and pressure. When the CO2 content reached 20%, the galvanic corrosion sensitivity factor was negative, which decreased first and then increased with the increase of temperature, and increased with the increase of salinity. Besides, the maximum galvanic corrosion rate was 69% higher than conventional corrosion rate.

In recent years, deep learning has made a breakthrough in the field of speech recognition, and pushes forward the wide application of speech recognition technology in people's daily lives. Further optimization of the speech recognition model needs to be supported by a larger scale calibrated data. However, the scale of the current open source audio data set is still too small, and corpus is mostly written language of news-based long texts. This paper, by talking about the popular speech recognition applications like human-computer interaction and intelligent customer service, builds and opens the largest ever Chinese Mandarin speech corpus DTZH1505 through crowdsourcing. Data set records natural speech of 6 408 speakers from 8 major Chinese dialect regions and 33 provinces, up to 1 505 hours and on various scenes like social networking, human-computer interaction, intelligent customer service and on-board commands. It can be widely used in the researches of corpus linguistics, conversation analysis, speech recognition, as well as speaker recognition. This paper implements a series benchmark speech recognition experiments, and the results show that: compared to the same scale Chinese speech corpus aishell2, the speech recognition model based on this data set has better performance. [ABSTRACT FROM AUTHOR]

Soil water and salt contents are key soil physical parameters that play a crucial role in soil-related hydrological, ecological, environmental, and agricultural processes. Time domain reflectometry (TDR) is commonly used to measure in-situ soil water and salt contents, and provide possible solutions to quickly obtain soil bulk density (BD). However, the measurement accuracy is greatly influenced by the interaction of soil water and salt contents on the measured soil dielectric constant and electrical conductivity, especially for salinized soils. To accurately estimate the soil gravimetric (GWC) and volumetric (VWC) water contents, soil salt content (TS), and BD based on the TDR measurements, we designed different model input schemes to quantify the effect of different soil factors, and applied eight machine learning algorithms to map the non-linear relationship between model inputs and each target soil property. Results of a case study in Hetao Irrigation District in Northwest China indicated that soil particle-size fractions (psfs) are important inputs to predict all the above soil properties. Furthermore, BD mainly contributes to the prediction of soil GWC, and soil surface temperature (T) is effective in improving the GWC and TS estimations. Among eight machine learning algorithms used, extreme gradient boosting (XGB) and gradient boosting regression tree (GBRT) showed good robustness and strong learning capacity. It is recommended to apply XGB to precisely estimate GWC and BD, which resulted in the coefficients of determination (R2) of 0.80 and 0.69, respectively. On the other hand, GBRT precisely estimated the VWC and TS with R2 of 0.71 and 0.84, respectively. The evaluation of spatial distribution characteristic indicated that it is reliable to obtain the spatial distributions of the above soil properties from the TDR measurements based on the recommended model input schemes and machine learning algorithms. [Display omitted] • We estimated soil water and salt contents and bulk density from TDR measurements. • Different input schemes and machine learning algorithms are evaluated. • Soil particle-size fractions are important for all the predicted soil properties. • Soil bulk density mainly contributes to the soil gravimetric water content (GWC). • It is reliable to apply the recommended model at the irrigation district scale. [ABSTRACT FROM AUTHOR]

A new series of nonlinear optical crystals LaxY1−xCa4O(BO3)3 (LaxY1−xCOB) with multiple components were grown by using the traditional Czochralski pulling method. X-ray powder diffraction and single-crystal X-ray diffraction experimental results proved that all these crystals formed in the LaxY1−xCOB solid solution state with a monoclinic structure of space group Cm. The optical birefringence was found to be adjustable by changing the compositional parameter x for the LaxY1−xCOB crystals. Taking advantage of the optical parametric oscillator laser, the non-critical phase-matching (NCPM) second-harmonic-generation (SHG) and third-harmonic-generation (THG) wavelengths along the Y-axis were determined at ambient temperature. In addition, the relationships between and among the optical birefringence, NCPM wavelength and crystal structure were discussed, and the NCPM SHG and THG of the 1064 nm laser were further achieved from the La0.120Y0.880COB and La0.140Y0.860COB crystals by adjusting the temperature, respectively. Using a 1064 nm Nd:YAG laser as the fundamental light source, the angular acceptance, temperature acceptance, and optical conversion efficiencies were determined and found to be on the order of 107.6 mrad, 18.3 °C and 48.8% for SHG of the La0.120Y0.880COB crystal, respectively, and 126.8 mrad, 68.6 mrad, 10.6 °C and 32.4% for THG of the La0.140Y0.860COB crystal, respectively. It is demonstrated that LaxY1−xCOB is a promising NLO crystal for NCPM frequency conversion applications in the visible and ultraviolet spectral regions. [ABSTRACT FROM AUTHOR]

In the field of nonlinear optics, cascaded frequency conversion is an effective method to obtain a solid-state laser source in the short wavelength region. By far, the most famous and popular frequency conversion approach is cascaded third-harmonic-generation (THG), which is composed of two steps: a phase-matching (PM) second-harmonic-generation, followed by a PM sum-frequency-generation. Correspondingly, two nonlinear optical (NLO) crystals are required. Theoretically, THG could be realized by utilizing only one crystal, as long as the frequency conversion processes occur at similar PM orientations and the polarization matching problem is solved. In this paper, we realized this approach by using one GdxY1-xCOB crystal; an ultrawide angular acceptance was observed because the SHG process was noncritical phase matching, thereby providing the advantages of large angular acceptance and freedom from beam walk-off as the optimum PM approach in the NLO domain. Compared to the traditional cascaded THG configuration that requires two crystals, this configuration possesses the advantages of small volume, compactness, and low cost, all of which are favorable for practical applications. [ABSTRACT FROM PUBLISHER]

A new series of nonlinear optical crystals LaxY1−xCa4O(BO3)3 (LaxY1−xCOB) with multiple components were grown by using the traditional Czochralski pulling method. X-ray powder diffraction and single-crystal X-ray diffraction experimental results proved that all these crystals formed in the LaxY1−xCOB solid solution state with a monoclinic structure of space group Cm. The optical birefringence was found to be adjustable by changing the compositional parameter x for the LaxY1−xCOB crystals. Taking advantage of the optical parametric oscillator laser, the non-critical phase-matching (NCPM) second-harmonic-generation (SHG) and third-harmonic-generation (THG) wavelengths along the Y-axis were determined at ambient temperature. In addition, the relationships between and among the optical birefringence, NCPM wavelength and crystal structure were discussed, and the NCPM SHG and THG of the 1064 nm laser were further achieved from the La0.120Y0.880COB and La0.140Y0.860COB crystals by adjusting the temperature, respectively. Using a 1064 nm Nd:YAG laser as the fundamental light source, the angular acceptance, temperature acceptance, and optical conversion efficiencies were determined and found to be on the order of 107.6 mrad, 18.3 °C and 48.8% for SHG of the La0.120Y0.880COB crystal, respectively, and 126.8 mrad, 68.6 mrad, 10.6 °C and 32.4% for THG of the La0.140Y0.860COB crystal, respectively. It is demonstrated that LaxY1−xCOB is a promising NLO crystal for NCPM frequency conversion applications in the visible and ultraviolet spectral regions. [ABSTRACT FROM AUTHOR]

Neomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are driver mutations in acute myeloid leukemia (AML) and other cancers. We report the development of new allosteric inhibitors of mutant IDH1. Crystallographic and biochemical results demonstrated that compounds of this chemical series bind to an allosteric site and lock the enzyme in a catalytically inactive conformation, thereby enabling inhibition of different clinically relevant IDH1 mutants. Treatment of IDH1 mutant primary AML cells uniformly led to a decrease in intracellular 2-HG, abrogation of the myeloid differentiation block and induction of granulocytic differentiation at the level of leukemic blasts and more immature stem-like cells, in vitro and in vivo. Molecularly, treatment with the inhibitors led to a reversal of the DNA cytosine hypermethylation patterns caused by mutant IDH1 in the cells of individuals with AML. Our study provides proof of concept for the molecular and biological activity of novel allosteric inhibitors for targeting different mutant forms of IDH1 in leukemia. [ABSTRACT FROM AUTHOR]

The protein Keap1 is central to the regulation of the Nrf2-mediated cytoprotective response, and is increasingly recognized as an important target for therapeutic intervention in a range of diseases involving excessive oxidative stress and inflammation. The BTB domain of Keap1 plays key roles in sensing environmental electrophiles and in mediating interactions with the Cul3/Rbx1 E3 ubiquitin ligase system, and is believed to be the target for several small molecule covalent activators of the Nrf2 pathway. However, despite structural information being available for several BTB domains from related proteins, there have been no reported crystal structures of Keap1 BTB, and this has precluded a detailed understanding of its mechanism of action and interaction with antagonists. We report here the first structure of the BTB domain of Keap1, which is thought to contain the key cysteine residue responsible for interaction with electrophiles, as well as structures of the covalent complex with the antagonist CDDO/bardoxolone, and of the constitutively inactive C151W BTB mutant. In addition to providing the first structural confirmation of antagonist binding to Keap1 BTB, we also present biochemical evidence that adduction of Cys 151 by CDDO is capable of inhibiting the binding of Cul3 to Keap1, and discuss how this class of compound might exert Nrf2 activation through disruption of the BTB-Cul3 interface. [ABSTRACT FROM AUTHOR]

Mitogen-Activated Protein Kinase (MAPK) pathway activation has been implicated in many types of human cancer. BRAF mutations that constitutively activate MAPK signalling and bypass the need for upstream stimuli occur with high prevalence in melanoma, colorectal carcinoma, ovarian cancer, papillary thyroid carcinoma, and cholangiocarcinoma. In this report we characterize the novel, potent, and selective BRAF inhibitor, dabrafenib (GSK2118436). Cellular inhibition of BRAFV600E kinase activity by dabrafenib resulted in decreased MEK and ERK phosphorylation and inhibition of cell proliferation through an initial G1 cell cycle arrest, followed by cell death. In a BRAFV600E-containing xenograft model of human melanoma, orally administered dabrafenib inhibited ERK activation, downregulated Ki67, and upregulated p27, leading to tumor growth inhibition. However, as reported for other BRAF inhibitors, dabrafenib also induced MAPK pathway activation in wild-type BRAF cells through CRAF (RAF1) signalling, potentially explaining the squamous cell carcinomas and keratoacanthomas arising in patients treated with BRAF inhibitors. In addressing this issue, we showed that concomitant administration of BRAF and MEK inhibitors abrogated paradoxical BRAF inhibitor-induced MAPK signalling in cells, reduced the occurrence of skin lesions in rats, and enhanced the inhibition of human tumor xenograft growth in mouse models. Taken together, our findings offer preclinical proof of concept for dabrafenib as a specific and highly efficacious BRAF inhibitor and provide evidence for its potential clinical benefits when used in combination with a MEK inhibitor. [ABSTRACT FROM AUTHOR]

The angular non-critical phase-matching (A-NCPM) second-harmonic-generation (SHG) properties of RE1xRE21−xCOB (RE1, RE2 = Y, Gd, La, Tm, Sm, and Nd) type mixed crystals including NCPM wavelength and conversion efficiency were detailedly investigated. Theoretical calculations manifest that the A-NCPM SHG scope of these crystals is 0.72~1.42 µm, and in experiments, the A-NCPM SHG waveband of 0.72~1.25 µm has been realized, by changing the ratio of the rare-earth elements RE1 and RE2 in RE1xRE21−xCOB crystals. Comparing to the temperature-dependent A-NCPM SHG of 0.95~1.34 µm in LiB3O5 (LBO) crystal, the composition-dependent A-NCPM SHG of 0.72~0.95 µm in RE1xRE21−xCOB type crystals is unique and has special significance for the frequency conversion of Ti:Sapphire lasers. Relationships between the birefringence and radius of rare-earth ion RE3+ in RE1xRE21−xCOB mixed crystals were discussed. Aiming for the A-NCPM SHG of 0.72~1.42 µm, we supply a clear, completed, and optimized solution on how to select the compositions of RE1xRE21−xCOB mixed crystals. Under focusing light beam conditions, high efficient A-NCPM SHG for both OPO and Ti:sapphire lasers were realized experimentally by using long Y- and Z-cut RE1xRE21−xCOB crystal samples. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The antioxidant natural product sulforaphane (SFN) is an oil with poor aqueous and thermal stability. Recent work with SFN has sought to optimize methods of formulation for oral and topical administration. Herein we report the design of new analogs of SFN with the goal of improving stability and drug-like properties. Lead compounds were selected based on potency in a cellular screen and physicochemical properties. Among these, 12 had good aqueous solubility, permeability and long-term solid-state stability at 23 °C. Compound 12 also displayed comparable or better efficacy in cellular assays relative to SFN and had in vivo activity in a mouse cigarette smoke challenge model of acute oxidative stress. [ABSTRACT FROM AUTHOR]

A bulk Nd:LaCa 4 O(BO 3) 3 (Nd:LaCOB) single crystal with the low Nd3+-doping concentration (~0.5 at%) was grown by Czochralski (Cz) method. Its powder X-ray diffraction, Nd3+ ions doping concentration, polarized transmittance and emission spectra, and fluorescence lifetimes were tested. Based on the Judd-Ofelt theory, the spectral parameters of Nd:LaCOB (Nd3+, ~0.5 at%) crystals including polarized absorption and emission cross sections, spontaneous transition probability, fluorescence branching ratio, theoretical fluorescence lifetime and intensity parameters (Ω 2 , Ω 4 and Ω 6) were systemically investigated. The calculated radiation lifetimes were compared with the experimental values, resulting in a quantum yield of 33%, which was the highest record among all the Nd:ReCOB (Re: Y, Gd, La 1−x Gd x) type crystals. The spectral properties of Nd:LaCOB were found to be better than those of Nd:YCOB and Nd:GdCOB crystals, especially in polarized absorption and emission cross sections. The self-frequency-doubling (SFD) angles were calculated according to the main fluorescence peaks of Nd:LaCOB (Nd3+, ~0.5 at%) crystals such as 1041 nm, 1060 nm, 1090 nm and 1102 nm, which would be excited and frequency doubled into blue-green, green, yellow-green and yellow lasers. All the results showed that the Nd:LaCOB crystals had potential applications in the field of laser and SFD. [ABSTRACT FROM AUTHOR]

Abstract: Soluble epoxide hydrolase (sEH, EPHX2) metabolizes eicosanoid epoxides, including epoxyeicosatrienoic acids (EETs) to the corresponding dihydroxyeicosatrienoic acids (DHETs), and leukotoxin (LTX) to leukotoxin diol (LTX diol). EETs, endothelium-derived hyperpolarizing factors, exhibit potentially beneficial properties, including anti-inflammatory effects and vasodilation. A novel, potent, selective inhibitor of recombinant human, rat and mouse sEH, GSK2256294A, exhibited potent cell-based activity, a concentration-dependent inhibition of the conversion of 14,15-EET to 14,15-DHET in human, rat and mouse whole blood in vitro, and a dose-dependent increase in the LTX/LTX diol ratio in rat plasma following oral administration. Mice receiving 10 days of cigarette smoke exposure concomitant with oral administration of GSK2256294A exhibited significant, dose-dependent reductions in pulmonary leukocytes and keratinocyte chemoattractant (KC, CXCL1) levels. Mice receiving oral administration of GSK2256294A following 10 days of cigarette smoke exposure exhibited significant reductions in pulmonary leukocytes compared to vehicle-treated mice. These data indicate that GSK2256294A attenuates cigarette smoke-induced inflammation by both inhibiting its initiation and/or maintenance and promoting its resolution. Collectively, these data indicate that GSK2256294A would be an appropriate agent to evaluate the role of sEH in clinical studies, for example in diseases where cigarette smoke is a risk factor, such as chronic obstructive pulmonary disease (COPD) and cardiovascular disease. [Copyright &y& Elsevier]

Abstract: Phosphoinositide 3-kinases have been targeted for therapeutic research because they are key components of a cell signaling cascade controlling proliferation, growth, and survival. Direct activation of the PI3Kα pathway contributes to the development and progression of solid tumors in breast, endometrial, colon, ovarian, and gastric cancers. In the context of a drug discovery effort, the availability of a robust crystallographic system is a means to understand the subtle differences between ATP competitive inhibitor interactions with the active site and their selectivity against other PI3Kinase enzymes. To generate a suitable recombinant design for this purpose, a p85α–p110α fusion system was developed which enabled the expression and purification of a stoichiometrically homogeneous, constitutively active enzyme for structure determination with potent ATP competitive inhibitors (Raha et al., in preparation) . This approach has yielded preparations with activity and inhibition characteristics comparable to those of the full-length PI3Kα from which X-ray diffracting crystals were grown with inhibitors bound in the active site. [Copyright &y& Elsevier]