Influence of Top Seal Damage on Contact Seal in Ram Blowout Preventer.

Top seal failure of ram blowout preventer (BOP) is one of the main factors leading to well control risk. The constitutive model and parameters of nitrile butadiene rubber (NBR) were optimized by compression and tensile tests, and the failure analysis model of the contact seal of the ram BOP top seal was built. The nonlinear contact mechanical behavior of the connection part of the BOP top seal was analyzed by the finite element method. Then, the influence of corrosion and wear defects at the top seal position of the 2FZ35-70 BOP under rated working pressure on the contact seal were studied, and the results showed that the overall contact pressure distribution of the top seal corrosion defects was uniform, the local contact pressure of the corrosion pit edge increased, and the top contact pressure decreased. The overall contact pressure of the wear defect of the top seal decreased linearly, the contact pressure at the maximum depth of the wear defect was the smallest, and the contact pressure gradually decreased to both sides. Ultimately, to guarantee the safety and reliability of the ram BOP, it is suggested that the acceptable depths of the seal corrosion pit and the wear at the top of the ram BOP are 4.0 mm and 0.2 mm, respectively, thus the reliability evaluation problem of the quantitative seal of the ram BOP top seal is solved.

[Research progress of Angelicae Sinensis Radix and predictive analysis on its quality markers].

Angelicae Sinensis Radix, as a medicinal and edible Chinese medicinal herb, is widely used in clinical practice. It is mainly cultivated in Minxian, Tanchang, Zhangxian and Weiyuan counties of Gansu province. In recent years, with the comprehensive and in-depth study of Angelicae Sinensis Radix in China and abroad, its chemical composition, pharmacological effects and application and development have attracted much attention. In this study, the chemical composition, traditional efficacy, and modern pharmacological effects of Angelicae Sinensis Radix were summarized. On this basis, combined with the core concept of quality markers(Q-markers), the Q-markers of Angelicae Sinensis Radix were discussed from the aspects of mass transfer and traceability and chemical composition specificity, availability, and measurability, which provided scientific basis for the quality evaluation of Angelicae Sinensis Radix.

Buried Defect Detection Method for a Blowout Preventer Seal Ring Groove Based on an Ultrasonic Phased Array.

This study aims to investigate an accurate detection method to detect defects in the gasket ring groove of the blowout preventer (BOP) using the ultrasonic phased array technology. Traditionally, it is difficult to accurately determine the type and size of defects in the gasket ring groove due to the complexity of the BOP configuration and the interference between the defect echo and the structural echo when using the ultrasonic phased array detection technology. In this study, firstly, the appropriate detection process parameters are determined by using simulation software for simulating and analyzing the defects of different sizes and types in the gasket ring groove of a BOP. Thereafter, according to the detection process parameters determined by the simulation analysis, we carry out a corresponding actual detection test. Simulation analysis and detection test results show that the relative amplitude of the test results and the simulation results differ within 1 dB, and the simulation results have a guiding role for the actual detection. The defect echo and structure echo can be clearly distinguished by selecting appropriate detection process parameters, such as probe frequency 5 MHz, array elements 36, and probe aperture 16 mm. The research results can provide theoretical reference for the detection of blowout preventer.

The complete mitochondrial genome of Xylotrechus namanganensis (Coleoptera: Cerambycidae).

The complete mitochondrial genome of Xylotrechus namanganensis was sequenced. The genome size was 15,565 bp, which consists of 13 protein-encoding genes, 22 tRNA-encoding genes, 2 rRNA-encoding genes and 1D-loop control region. The base composition of mitogenome was biased toward A + T content, of which was 73.21%. The phylogenetic tree based on complete mitogenome sequences revealed that T. namanganensis had a closer relationship with X. grayii.

Phytochemical Profile and Anti-Inflammatory Activity of the Fraction from Artemisia lavandulaefolia.

Artemisia lavandulaefolia, a traditional herbal medicine, has been utilized as anti-inflammatory and analgesia agent in clinic. Bioassay-guided fractionation resulted in a fraction (ALDF) with anti-inflammatory effect obtained from A. lavandulaefolia. Its main constituents were analyzed and identified by UPLC-ESI-Q-TOF-MS technology. ALDF showed the strong inhibitory activity on the nitrogen oxide (NO) production in LPS-induced RAW 264.7 macrophages with an IC50 value of 1.64±0.41 µg/mL. Further results displayed that ALDF also significantly suppressed the secretion of key pro-inflammatory mediators, including tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2 ) and interleukin-1ß (IL-1ß), and the increase of the inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression induced by LPS stimulation. Mechanism study indicated that ALDF was able to block NF-κB signaling pathway through inhibiting IκB and p65 phosphorylation, as well as NF-κB p65 nuclear translocation. Furthermore, in vivo results in mice revealed that treatments with ALDF evoked significant inhibition on ear edema induced by xylene and on the writhing responses induced by acetic acid. These results suggest that ALDF holds great potential in the prevention and treatment of inflammatory disorders.

Nitric Oxide Production Inhibitory Eudesmane-Type Sesquiterpenoids from Artemisia argyi.

Six new eudesmane-type sesquiterpene derivatives, artemargyinins A-F were isolated from the leaves of Artemisia argyi. Their structures were elucidated based on the extensive analysis of spectroscopic data. Artemargyinins A-F feature a lactone ring-opening eudesmane-type sesquiterpene with an isoprenoid group at C(8). All compounds were tested for their inhibitory effects on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 macrophages. Artemargyinins A-F showed more potent NO production inhibitory activity with IC50 values ranging from 7.66±0.53 to 61.19±2.54 µM than the positive control quercetin (IC50 =74.34±1.39 µM). Among them, artemargyinins C and D exhibited strong inhibitory activity with IC50 values of 8.08±0.21 and 7.66±0.53 µM, respectively.

Triterpenoids with α-glucosidase inhibitory activity from Artemisia argyi.

Two new nordammarane-type triterpenoids, 3ß-acetoxy-20-oxo-21-nordammaran-23-carboxylic acid methyl ester (1) and 3ß-acetoxy-17ß-dammaranic acid (2), along with two known cycloartane-type triterpenoids (3-4), were isolated from the petroleum ether-soluble extract of Artemisia argyi. Their structures were elucidated based on 1D and 2D NMR spectroscopic data analysis. All compounds were evaluated for their α-glucosidase inhibitory activity in vitro. Compounds 1-4 exhibited significant inhibitory effects on α-glucosidase with IC50 values ranging from 38.34 ± 0.23 to 105.54 ± 0.33 µM.

Sesquiterpenoids from Artemisia argyi and their COXs inhibitory activities.

Four new sesquiterpene lactones, named artemargyinolides A-D (1-4), and seven known sesquiterpenoids (5-11) were isolated from Artemisia argyi. Their structures were elucidated based on the extensive analysis of spectroscopic data. The absolute configuration of 1 was assigned by X-ray crystallographic analysis. Compound 1 is an unprecedented sesquiterpene dimer-monoterpene lactone. The cyclooxygenases (COX-1 and COX-2) inhibitory activities of all isolated compounds were evaluated. Compounds 1, 2, 4, and 6-11 showed inhibitory activity against COX-2 with IC50 values ranging from 35.78 ±â€¯0.39 to 256.07 ±â€¯0.38 µM. However, compounds 7, 9, and 10 exhibited weak inhibitory activity against COX-1 with IC50 values of 465.70 ±â€¯1.53, 281.43 ±â€¯3.56, and 490.45 ±â€¯6.07 µM, respectively. Other compounds are inactive against COX-1. Therefore, compounds 1, 2, 4, 6, 8, and 11 displayed selective COX-2 inhibitory activity.

Process alarm prediction using deep learning and word embedding methods.

Industrial alarm systems play an essential role for the safe management of process operations. With the increase in automation and instrumentation of modern process plants, the number of alarms that the operators manage has also increased significantly. The operators are expected to make critical decisions in the presence of flooding alarms, poorly configured and maintained alarms and many nuisance alarms. In this environment, if the incoming alarms can be correctly predicted before they actually occur, the operators may have a chance to address and possibly avoid abnormal behaviors by taking corrective actions in time. Inspired by the application of deep learning in natural language processing, this paper presents an alarm prediction method based on word embedding and recurrent neural networks to predict the next alarm in a process setting. This represents both a novel approach to alarm management as well as a novel application of natural language processing and deep learning techniques to this problem. The proposed method is applied to an actual case study to demonstrate its performance.

[Research progress on anti-inflammatory mechanism of natural sesquiterpenoids].

Sesquiterpenoid is a kind of compound widely distributed in nature, which has a wide range of biological activities, such as anti-inflammatory, anti-tumor and immunomodulatory activities. This paper would review the anti-inflammatory mechanism of sesquiterpenoid. The mechanism is mainly by inhibiting the activation of nuclear factor (NF-κB), mitogen-activated protein kinase (MAPKs) and signal transducers and activators of transcription (STAT) signaling pathways and down-regulating the inflammatory gene expression including tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2), nitric oxide (NO), interleukin-1(IL-1), IL-6, IL-8 and other inflammatory factors. Thereby, the production and release of inflammatory cytokines are reduced to exert anti-inflammatory effect. This review is intended to provide reference for related research.

A Blade Defect Diagnosis Method by Fusing Blade Tip Timing and Tip Clearance Information.

Blade tip timing (BTT) technology is considered the most promising method for blade vibration measurements due to the advantages of its simplicity and non-contact measurement capacity. Nevertheless, BTT technology still suffers from two problems, which are (1) the requirements of domain expertise and prior knowledge of BTT signals analysis due to severe under-sampling; and (2) that the traditional BTT method can only judge whether there is a defect in the blade but it cannot judge the severity and the location of the defect. Thus, how to overcome the above drawbacks has become a big challenge. Aiming at under-sampled BTT signals, a feature learning method using a convolutional neural network (CNN) is introduced. In this way, some new fault-sensitive features can be adaptively learned from raw under-sampled data and it is therefore no longer necessary to rely on prior knowledge. At the same time, research has found that tip clearance (TC) is also very sensitive to the blade state, especially regarding defect severity and location. A novel analysis method fusing TC and BTT signals is proposed in this paper. The goal of this approach is to integrate tip clearance information with tip timing information for blade fault detection. The method consists of four key steps: First, we extract the TC and BTT signals from raw pulse data; second, TC statistical features and BTT deep learning features will be extracted and fused using the kernel principal component analysis (KPCA) method; then, model training and selection are carried out; and finally, 16 sets of experiments are carried out to validate the feasibility of the proposed method and the classification accuracy achieves 95%, which is far higher than the traditional diagnostic method.

Phthalide dimers from Angelica sinensis and their COX-2 inhibition activity.

Four new dimeric phthalides, angesinenolides C-F (1-4), along with three known ones, were isolated from the roots of Angelica sinensis. Their structures were determined by means of HRMS and NMR experiments. The structures of compounds 1 and 3 were confirmed using X-ray crystallographic data. All isolated compounds were tested for activities on the inhibition of COX-2 enzyme in vitro. Compounds 1-6 exhibited inhibitory activity against COX-2 with IC50 values ranging from 29.32 ±â€¯0.07 to 137.91 ±â€¯0.24 µM.

Sesquiterpene Lactones with COX-2 Inhibition Activity from Artemisia lavandulaefolia.

Two new sesquiterpene lactones, artelavanolides A (1) and B (2), and four known sesquiterpene lactones (3 - 6) were isolated from the leaves of Artemisia lavandulaefolia. Their structures were elucidated based on the analysis of spectroscopic data (1D, 2D-NMR and HR-ESI-MS). The absolute configuration of 1 was determined by the analysis of single-crystal X-ray diffraction data. Artelavanolide A (1) is a rare sesquiterpene lactone possessing an unusual skeleton with the linkage of Me(14)-C(1) that is probably formed through a rearrangement of the guaiane-type sesquiterpenoids. Artelavanolide B (2) is a new highly unsaturated guaianolide. Compounds 1 - 6 were tested for activities on the inhibition of COX-2 enzyme in vitro. All of compounds exhibited inhibitory activity against COX-2 with IC50 values ranging from 43.29 to 287.07 µm compared with the positive control, celecoxib (IC50 = 18.10 µm). Among them, 3 showed the best COX-2 inhibitory activity with an IC50 value of 43.29 µm.

Two new flavonoids from Artemisia argyi with their anticoagulation activities.

A new flavone glycoside, eupatilin 7-O-ß-d-glucopyranoside (1) and a new flavone, 5,6,2',4'-tetrahydroxy-7,5'-dimethoxyflavone (2), were isolated from Artemisia argyi. Their structures were unambiguously elucidated by extensive spectroscopic analysis. Both flavonoids were evaluated for in vitro anticoagulation activities. Compound 1 significantly extended thrombin time. Compound 2 had obvious effect in increasing prothrombin time.

A new size-expanded RNA alphabet: Computational design of benzo-homologated (xtz-) isothiazole RNA and comparisons to the x-thieno RNA.

Fluorescent nucleobase analogs are of great interest because of their widespread applications in nucleic acids research. In the present work, a new benzo-homologated RNA alphabet comprising xtzA, xtzG, xtzC, and xtzU was computationally designed based on the isomorphic tz-bases. The structural, electronic, and photophysical properties are studied by means of DFT and TDDFT calculations, and the effects of water solution, ribose, and base pairing on the singlet excited transitions were examined. The results are compared with those for tz-bases and xth-bases. These new base analogs can form stable Watson-Crick base pairs with natural counterparts as tz-bases and xth-bases do. Their ionization potentials and HOMO-LUMO gaps are in the middle of tz-bases and xth-bases: xth-base < xtz-base < tz-base. Furthermore, all xtz-bases are predicted to have smaller IPs and HOMO-LUMO gaps than natural bases and tz-bases, they are suggested to be candidates for applications in nanowire technology. The S1 states for all xtz-bases are revealed to be ππ* dominated by the configuration HOMO→LUMO. In water solution, compared with tz- or xth-bases, the lowest ππ* states are about 20.06-21.91kcal/mol red-shifted or 0.92-4.15kcal/mol blue-shifted, respectively. Linking to ribose has negligible effects on the S1 excitation energies, but it owns a larger impact on the corresponding oscillator strengths. Base pairing and water solution as a whole has very little effects on the S1 transition energies of xtzA and xtzC, but it will red-shift those for xtzG and xtzU by 6.69 and 5.30kcal/mol, respectively. All xtz-bases are expected to display visible fluorescence with the wavelengths predicted to be 540, 585, 524, and 506nm for xtzA, xtzG, xtzC and xtzU, respectively, in water solution. Though structurally very similar, the excitation maxima and fluorescence emissions of xtz- and xth-bases show distinct differences, allowing them to be distinguished from each other by their spectroscopic characters.

Phthalide Derivatives with Anticoagulation Activities from Angelica sinensis.

Two new phthalide derivatives, angesinenolides A and B (1 and 2), were isolated from the roots of Angelica sinensis. Their structures were elucidated using HRMS, NMR, and X-ray crystallographic data. Compound 1 is the first example of a phthalide trimer presumably formed through two [2+2] cycloaddition reactions. Compound 2 is a unique dimeric phthalide with a peroxy bridge between C-3a and C-6. Both phthalides were evaluated for in vitro anticoagulation activities. Compound 1 reduced the level of fibrinogen (FIB). Compound 2 significantly extended thrombin time and activated partial thromboplastin time, as well as markedly reduced the content of FIB.

Isoprenylated Flavonoids with PTP1B Inhibition from Macaranga denticulata.

Three new C-methylated and isoprenylated chalcone derivatives, dentichalcones A-C (1-3), together with six known compounds (4-9), were isolated from the twigs and leaves of Macaranga denticulata. Their structures were elucidated by spectroscopic analysis, including 1D, 2D NMR, and MS data. The known compounds, (2E)-1-(5,7-dihydroxy-2,2,6-trimethyl-2H-benzopyran-8-yl)-3-(4-methoxyphenyl)-2-propen-1-one (4), (2E)-1-(5,7-dihydroxy-2,2-dimethyl-2H-benzopyran-8-yl)-3-phenyl-2-propen-1-one (5), laxichalcone (6), macarangin (7), bonanniol A (8), and bonannione A (9), showed inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) in vitro. Three new C-methylated and isoprenylated chalcone derivatives, dentichalcones A-C (1-3), together with six known compounds, were isolated from the twigs and leaves of Macaranga denticulata. Some compounds showed inhibitory activities against PTP1B in vitro.

[The Study of Infrared Spectra of Acetophenone Molecule].

By implying the density functional theory method, the geometry of acetophenone molecular is fully optimized at the B3LYP/6-311++G(d, p) level and the frequency is also calculated at the same level. The infrared spectrum and complete vibrational modes of acetophenone molecular are attained. Meanwhile, the infrared spectrum is obtained by experimental measurements. Through the comparison and analysis, it is found that the theoretical calculation results meet well with those of experiments. Finally, the vibrational modes of acetophenone molecule are assigned, and the strong vibration peaks in the experiment results belong to infrared characteristic peaks of acetophenone molecule.

New size-expanded RNA nucleobase analogs: a detailed theoretical study.

Fluorescent nucleobase analogs have attracted much attention in recent years due to their potential applications in nucleic acids research. In this work, four new size-expanded RNA base analogs were computationally designed and their structural, electronic, and optical properties are investigated by means of DFT calculations. The results indicate that these analogs can form stable Watson-Crick base pairs with natural counterparts and they have smaller ionization potentials and HOMO-LUMO gaps than natural ones. Particularly, the electronic absorption spectra and fluorescent emission spectra are calculated. The calculated excitation maxima are greatly red-shifted compared with their parental and natural bases, allowing them to be selectively excited. In gas phase, the fluorescence from them would be expected to occur around 526, 489, 510, and 462 nm, respectively. The influences of water solution and base pairing on the relevant absorption spectra of these base analogs are also examined.

[Theory study of the structures and IR of (C5H5N)n(H2O), (n = 1-2, m = 1-4) clusters].

Using density functional theory, the possible geometrical structures of (C5H5N)n (H2O)m (n = 1-2, m = 1- 4) clusters were optimized at the B3LYP/6-311++G(d, p) level and the stable structures were attained. For the dimer formed between C5H5N and H2O, the calculation result shows that there is only one stable structure and the configuration of cluster formed through pi hydrogen bond (O-H...pi) interaction was not found. In order to study the stability of the clusters, the total energies and binding energies of the clusters were calculated at the same level of theory, and the result shows that the four-membered ring structures of water molecules in (C5H5N)n (H2O)4 (n = 1-2) clusters are more stable than structures of the triatomic ring of water molecules. The lowest energy structure of the C5H5N (H2O)4 cluster is more stable than the others and is probably a magic number structure by the analysis to the energy gap between HOMO and LUMO. At the end, the IR spectra of (C5H5N)n (H2O)m (n = 1-2, m = 1-4) clusters were analysed and the stronger peaks appearing in infrared spectra were assigned.