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In the application of electrolytic water splitting, MXenes can achieve performance optimization by doping, surface functional group regulation, construction of defect/vacancy, 3D/porous structure, or compounding with other materials.

Herein the effects of metal type, active site coordination structure, and coordination environment of SACs on CO2RR are discussed in detail. And the challenges and future development directions of SACs in the field of CO2RR are analyzed.

This review summarizes the preparation methods of MXene and the applications of MXene in electrocatalytic hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction and nitrogen reduction reaction.

Terpene cyclization, one of the most complex chemical reactions in nature, is generally catalyzed by two classes of terpene cyclases (TCs). Cytochrome P450s that act as unexpected TC-like enzymes are known but are very rare. Here, we genome-mined a cryptic bacterial terpenoid gene cluster, named ari, from the thermophilic actinomycete strain Amycolatopsis arida. By employing a heterologous production system, we isolated and characterized three highly oxidized eunicellane-derived diterpenoids, aridacins AC (13), that possess a rare 6/7/5-fused tricyclic scaffold. In vivo and in vitro experiments systematically established a non-canonical two-step biosynthetic pathway for diterpene skeleton formation. First, a class I TC (AriE) cyclizes geranylgeranyl diphosphate (GGPP) into a 6/10-fused bicyclic cis-eunicellane skeleton. Next, a cytochrome P450 (AriF) catalyzes cyclization of the eunicellane skeleton into the 6/7/5-fused tricyclic scaffold via C2-C6 bond formation. Quantum chemical computations support a hydrogen abstraction and subsequent oxidation mechanism for AriF catalyzed carbocation cyclization. The biosynthetic logic of skeleton construction in the aridacin diterpenoids is unprecedented, expanding the catalytic capacity and diversity of P450s and setting the stage to investigate the inherent principles of carbocation generation by P450s in the biosynthesis of terpenoids.

Interferon regulatory factor-7 (IRF7) is an essential regulator of both innate and adaptive immunity. It is also expressed in the otic vesicle of zebrafish embryos. However, any role for irf7 in hair cell development was uncharacterized. Does it work as a potential deaf gene to regulate hair cell development? We used whole-mount in situ hybridization (WISH) assay and morpholino-mediated gene knockdown method to investigate the role of irf7 in the development of otic vesicle hair cells during zebrafish embryogenesis. We performed RNA sequencing to gain a detailed insight into the molecules/genes which are altered upon downregulation of irf7. Compared to the wild-type siblings, knockdown of irf7 resulted in severe developmental retardation in zebrafish embryos as well as loss of neuromasts and damage to hair cells at an early stage (within 3 days post fertilization). Co-injection of zebrafish irf7 mRNA could partially rescued the defects of the morphants. atp1b2b mRNA injection can also partially rescue the phenotype induced by irf7 gene deficiency. Loss of hair cells in irf7-morphants does not result from cell apoptosis. Gene expression profiles show that, compared to wild-type, knockdown of irf7 can lead to 2,053 and 2,678 genes being upregulated and downregulated, respectively. Among them, 18 genes were annotated to HC development or posterior lateral line (PLL) development. All results suggest irf7 plays an essential role in hair cell development in zebrafish, indicating that irf7 may be a member of deafness gene family. This article is protected by copyright. All rights reserved.

The development of new responsive smart materials has been highly desirable in the recent decade due to growing demand in our daily life, and extended viologen-based coordination polymers are regarded as proper and promising candidates for stimuli-responsive study. A tri(pyridinyl)pyridine viologen-based Kagome dual (kgd) topological coordination polymer, [Mn3Cl4(tpptb)2]·Cl2·(H2O)2, (tpptb = N,N',N″-tri(3-carboxybenzyl)-2,4,6-tri(pyridinium-4-yl)pyridine; 1) has been solvothermally synthesized, which can selectively respond to soft X-ray Al-Kα (λ = 8.357 A) irradiation but not to UV light and hard X-rays of λ < 1.5418 A at room temperature. Appealingly, 1 is very sensitive and convenient for the visual detection of various volatile amine vapors, especially ethylamine vapors at a low concentration of 100 ppm, and the vapochromic sample can be recovered after exposure in the air at room temperature. The sequence of amines in vapochromism could be rationalized by combined consideration of vapor pressure, the molecular size, and electron-donor ability of various amine molecules as well as the void spaces of 1. In addition, 1 exhibits an obvious hydrochromic transformation upon heating in the air and an anhydrous atmosphere. Combined XPS and EPR confirmed that these physical and chemical stimuli can cause electron transfer from electron-rich groups to quaternary nitrogen atoms of the ligand to generate charge-separated radicals, leading to soft X-ray-induced photochromic and selective vapochromic behavior of 1. Such behavior indicates that it will become a convenient, recyclable, and practical multifunctional material for chemical and environmental sensing. These results provide an effective avenue for the rational design and synthesis of multifunctional chromic materials for potential use in sensing devices.

Oncolytic viruses armed with therapeutic transgenes of interest show great potential in cancer immunotherapy. Here, a novel oncolytic adenovirus carrying a signal regulatory protein‐α (SIRPα)‐IgG1 Fc fusion gene (termed SG635‐SF) was constructed, which could block the CD47 ‘don't eat me’ signal of cancer cells. A strong promoter sequence (CCAU) was chosen to control the expression of the SF fusion protein, and a 5/35 chimeric fiber was utilized to enhance the efficiency of infection. As a result, SG635‐SF was found to specifically proliferate in hTERT‐positive cancer cells and largely increased the abundance of the SF gene. The SF fusion protein was effectively detected, and CD47 was successfully blocked in SK‐OV3 and HO8910 ovarian cancer cells expressing high levels of CD47. Although the ability to induce cell cycle arrest and cell death was comparable to that of the control empty SG635 oncolytic adenovirus in vitro, the antitumor effect of SG635‐SF was significantly superior to that of SG635 in vivo. Furthermore, CD47 was largely blocked and macrophage infiltration distinctly increased in xenograft tissues of SK‐OV3 cells but not in those of CD47‐negative HepG2 cells, indicating that the enhanced antitumor effect of SG635‐SF was CD47‐dependent. Collectively, these findings highlight a potent antitumor effect of SG635‐SF in the treatment of CD47‐positive cancers., A SIRPα‐Fc fusion protein enhances the antitumor effect of oncolytic adenovirus against CD47‐positive ovarian cancer.

Objective To explore the relationship of life events, negative cognitive processing bias (NCPB) and mental health of recruits. Methods The Life Events Scale (LES), NCPB questionnaire and Military Mental Health Scale (MHS) were used for investigation in 2193 recruits from a certain troop. The SPSS 22.0 software was used to analyze the data. T-test and ANOVA were adopted to explore the influence of demographic factors on the mental health of recruits. Correlation analysis was performed to investigate the relationship of life events and NCPB to the mental health of recruits. The influence of life events and NCPB on the mental health of recruits was investigated by regression analysis. The mediating effect analysis was conducted for in-depth discussing the influence of NCPB in life events on the mental health of recruits. Results Male and highly educated recruits had significantly higher scores in mental health ability and quality (P

A phenylhexyl isothiocyanate (PITC) precolumn derivatization quantitative analysis of multicomponents by a single marker (QAMS) strategy for the simultaneous analysis of 20 free amino acids (FAA) in Dendrobium huoshanense is proposed. The method was validated by the linearity, limit of detection (LDO), and limit of quantitation (LOQ), recovery, precision, and stability. The results showed that when applying the established method, the LOQ of the FFAs was lower than 1 ng/ml except threonine (1.32 ng) and cysteine (1.16 ng). The QAMS investigation revealed that, using any one of the 20 FAAs as the reference internal standard, no significant differences were observed between the external standard method and the QAMS method for the quantification of FAAs in D. huoshanense by PITC precolumn derivatization [The relative standard deviation (RSD, %) by QAMS and ESM were all below 5%]. HPLC fingerprint investigation combined with similar analysis (the similarity values for S1-S25 were >0.875) and quality fluctuation analysis showed that the cultivation environment might have a great effect on the accumulation of FAAs in D. huoshanense. Overall, our study showed that we might increase the accuracy and scope of the simultaneous quantification of multicomponents using the QAMS technique by being derivatized with a strong UV absorbing group, and QAMS combined with chromatographic fingerprinting can be considered good quality criteria for the quality control of D. huoshanense and may provide analytical technical support for research on Maillard Reaction during the further processing of D. huoshanense.

One of the current research hotspots in educational data mining is to predict their online academic performance. The prediction results can provide personalized guidance for learners and teaching strategies. At present, performance prediction methods often ignore the fact that different behavior characteristics have different effects on performance. Therefore, this paper proposed an e-Learning performance prediction method based on attention mechanism. This method calculated the attention score of each behavior feature, then assigned the corresponding attention weight to each behavior feature. So, by this way, different behavior features have different influence on academic performance. The experimental results show that this method can predict e-Learning performance more accurately than other methods.

With the development of educational data mining and artificial intelligence, it has become a trend to use online learning data to evaluate students’ performance. Academic procrastination is an important performance of online learning and has a negative impact on academic performance. To address the problem of academic procrastination, this paper constructed an online learning academic procrastination prediction model. Task completion times and engagement performance were converted feature vectors. K-means algorithm was used to label the behaviors as procrastinators and non-procrastinators. Five classification algorithms were used to predict academic procrastination, and the performance of different classification algorithms was evaluated. The study found that the academic procrastination prediction model has good performance in predicting procrastination. It is expected that the findings of this paper will provide some warning for procrastinators, and encourage students to keep learning enthusiasm and initiative, and improve learning performance.

Academic procrastination is common among college students, which has seriously affected their academic and physical and mental health. The analysis of online learning behavior log data can help to diagnose students' procrastination tendency. Aiming at the phenomenon of academic procrastination of college students in the process of online learning, this paper firstly extracts five characteristic variables that represent the degree of task procrastination, and divides them into two categories: the degree of task procrastination in class and the degree of task procrastination after class according to different scenarios, students' behavior patterns may be different. Then, multi-view clustering method is used to divide students into three types of procrastinators. Finally, clustering tags are extracted to analyze the characteristics of procrastinators by combining five feature variables and learning performance. The experimental results show that the clustering performance of multi-view clustering algorithm is better than that of K-means algorithm; students' learning behavior patterns are different when facing in-class tasks and after-class tasks. Compared with after-class tasks, the procrastination degree of students in the face of in-class tasks is smaller; the procrastination degree of students’ after-class tasks is more consistent.

To investigate the effects of morin-regulated NLRP3/Caspase-1 pathway on experimental autoimmune thyroiditis in rats.The rats were randomly assigned to 6 groups: control group, experimental autoimmune thyroiditis group (EAT), low-, medium- and high-dose morin groups (post-modeling gavage of 50, 100 and 200 mg/kg morin hydrate per day for 6 weeks) and tripterygium wilfordii polyglycosides group (LGT group, post-modeling gavage of 6.25 mg/kg tripterygium wilfordii polyglycosidesper day for 6 weeks). Except for the control group, the rat model of experimental autoimmune thyroiditis was established by subcutaneous injection of 0.1 mL incomplete Freund's adjuvant containing porcine thyroglobulin. The levels of serum thyroglobulin (TgAb), thyroid peroxidase antibody (TPOAb), triiodothyronine (T3) and tetraiodothyronine (T4) in serum were detected by radioimmunoassay. The mRNA levels of interleukin-17 (Compared with the EAT group, serum levels of TPOAb, TgAb, T3, and T4 in low-, medium- and high-dose Morin groups and LGT group were reduced (The findings suggest that Morin improved experimental autoimmune thyroiditis in rats through regulating NLRP3/Caspase-1 pathway.

Aim: The resident bacterial microbiome may shape and protect the health of vertebrate host. An array of molecules secreted by microbiome may contribute to the ecological stability of the microbiome itself. Material & methods: ELISA, radioactivity, immunofluorescence and cytokines measurements were used to observe the bioactivity and stability of colicin Ia level in oviparous and viviparous animal circulation. Results: Colicin Ia, a protein antimicrobial produced by Escherichia coli, is not present in animals at birth, but increases in concentration with the establishment of a stable gut microbiome and drops when the microbiome is experimentally disrupted. Colicin introduced in vivo is transported to tissues at concentrations able to prevent or eliminate bacterial infection. Conclusion: Our findings suggest an unexpected benefit provided by the presence of a resident microbiome in the form of active, circulating, bacterially-synthesized antimicrobial molecules.

Enzymatic degradation with laccase is a green option for removal of organic compounds from aqueous media. However, the development of high-performance support for immobilization of enzyme is constantly required for the advancement of this technology. In this study the laccase was facilely immobilized on graphene oxide (GO) nanosheets separation membrane, and the membrane’s performance as laccase immobilization carrier has been investigated. The results showed that the immobilized laccase on GO-PES membrane exhibited excellent stability towards temperature and pH in the long term and the flux of pure water of biocatalytic membrane was enhanced as well. Synthetic dye degradation was carried out with four representative dyes with different molecular size and structure. The biocatalytic membrane showed substantial improvement of these dyes degradation compared with the GO-PES membrane without laccase immobilized. The relative activity order of the immobilized laccase for the degradation of these dyes was Reactive Brilliant Blue (K-GR) > Reactive Brilliant Blue (KN-R) > Methyl Orange (MO) > Crystal Violet (CV). This order was discussed in terms of correlation between molecular size and structure of dye species. GO coating membranes with catalytic property of laccase offer a new potential approach towards synthetic dye degradation.

Objectives: To investigate the diagnostic accuracy of ultrasound for evaluation of inflammatory activity in patients with Crohn’s disease (CD). Methods: Fifty-six patients with histologically proven CD (39 with active, 17 with inactive disease) and 30 healthy volunteers as a control group were enrolled in the study at WeiFang People’s Hospital, Weifang Province, China from October 2012 to December 2014. Bowel wall thickness, and vascularity pattern were measured by Doppler ultrasound. Results: There was a significant difference in flow volume of the superior mesenteric artery (585 ± 235 ml/min) in the patients with active disease, compared with those with inactive disease (401 ± 238 ml/min) and the control group (390 ± 189 ml/min, p less than 0.001). Wall thickness was 5.1 ± 1.5 mm in the active CD group, 3.3 ± 1.6 mm in the inactive disease group ( p less than 0.001) and less than 3 mm in the control group. Resistance index in the thickened bowel wall showed some differences: 0.68 ± 0.05 in the active disease group, 0.78 ± 0.08 in the inactive disease group, and 0.85 ± 0.07 in the control group ( p less than 0.05). Conclusion: Doppler ultrasound is a useful diagnostic tool in detecting CD and assessing inflammatory activity. Saudi Med J 2017; Vol. 38 (4): 391-395 doi: 10.15537/smj.2017.4.17855 How to cite this article: Na Y, Zhou J, Xiao XM, Zhang WX, Gao HL, Wang Y, et al. Assessment of Crohn's disease activity by Doppler sonography. Saudi Med J. 2017 Apr;38(4):391-395. doi: 10.15537/smj.2017.4.17855.

The small watershed is the basic unit of soil erosion control on the Loess Plateau. Consequently, the study of the spatial distribution and influencing factors of vegetation is the basis of vege-tation restoration and reconstruction in this region. A small watershed in the wind-water erosion crisscross region with the most serious soil erosion in the Loess Plateau was selected to investigate the changes of vegetation distribution and soil properties. The spatial variability of plant community characteristics and its main driving factors were studied by geo-statistical method and redundancy analysis (RDA). The results showed that there were 27 plant species in the small watershed, belonging to 12 families and 25 genera. Leguminous, Gramineous and Compositae plants were dominant families, contributing 59.3% of the total species. In general, the community structure was simple and the organization level was low. The aboveground biomass (AGB) and coverage (C) of the community reached 205.7 g·m小流域是黄土高原水土流失治理的基本单元,对其植被的空间分布特征和影响因素研究是该地植被恢复和重建的基础.为此,在黄土高原水土流失最为严重的水蚀风蚀交错带选取一小流域,调查了其植被分布与土壤性质等的变化,并用地统计学方法和冗余分析(RDA)方法研究了植物群落特征的空间变异特征及其主要影响因子.结果表明: 该小流域共有植物27种,隶属于12科25属,以豆科、禾本科和菊科植物最多,占种总数的59.3%;总体上群落结构简单、组织水平低.群落地上生物量(AGB)和盖度(

Vascular endothelial growth factor 2 (VEGFR2) was initially identified as a receptor of VEGF on endothelial cells with a role in regulating angiogenesis during organism development and tumorigenesis. Previously, in cancer tissue, VEGFR2 has been reported to be expressed in endothelial cells. In our research, we found that VEGFR2 was expressed not only in endothelial cells but also cancer cells in head and neck squamous cell carcinomas (HNSCCs). Knockdown of VEGFR2 in Hep2 cells could arrest the cell cycle in G0/G1, leading to a decrease in proliferation. We also present evidence that MAPK/ERK signal pathways and expression of CDK1 downstream of VEGFR2 might regulate proliferation and cell cycle arrest. Furthermore, we discovered that down-regulate VEGRF2 in Hep2 cells could significantly affect the invasion ability. Taken together, our data suggest that VEGFR2 might regulate proliferation and invasion in HNSCC cancer cells in vivo.

Herein, we report the synthesis and characterization of Ce(III)-doped UiO-66 nanocrystals, revealing their potential to efficiently remove organic dyes such as methylene blue (MB), methyl orange (MO), Congo red (CR), and acid chrome blue K (AC) from aqueous solutions. Specifically, the room-temperature adsorption capacities of Ce(III)-doped UiO-66 equaled 145.3 (MB), 639.6 (MO), and 826.7 (CR) mg g−1, exceeding those reported for pristine UiO-66 by 490, 270, and 70%, respectively. The above behavior was rationalized based on zeta potential and adsorption isotherm investigations, which revealed that Ce(III) doping increases the number of adsorption sites and promotes π–π interactions between the adsorbent and the adsorbate, thus improving the adsorption capacity for cationic and anionic dyes and overriding the effect of electrostatic interactions. The obtained results shed light on the mechanism of organic dye adsorption on metal–organic frameworks, additionally revealing that the synergetic interplay of electrostatic, π–π, and hydrophobic interactions results in the operation of two distinct adsorption regimes depending on adsorbate concentration.

Qin-lan Chen,1 Xiao-ying Zhao,2 Xiao-mi Wang,1 Na Lv,2 Ling-ling Zhu,3 Hui-min Xu,4 Quan Zhou4 1Radiology Nursing Unit, Division of Nursing, 2Department of Quality Management, 3Geriatric VIP Care Ward, Division of Nursing, 4Department of Pharmacy, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, People’s Republic of China Abstract: The authors retrospectively analyzed the pattern and characteristics of non-laboratory-based adverse drug reactions (ADRs) induced by intravenous radiocontrast agents in a large-scale hospital in China during 2014–2015. There were 314 ADR cases among 118,208 patients receiving enhanced CT or MRI examinations. The frequency of moderate/severe ADRs defined by Chinese Society of Radiology (ie, severe vomiting, systematic urticaria, facial swelling, dyspnea, vasovagal reaction, laryngeal edema, seizure, trembling, convulsions, unconsciousness, shock, death, and other unexpected adverse reactions) was rare (0.0431%), whereas the mild ADRs were uncommon (0.2225%) and accounted for 83.76% of ADRs. Frequency of ADRs induced by iodinated contrast agents was related with examination site, sex, and type of patient settings (P

Riccardin D, a liverwort-derived naturally occurring macrocyclic bisbibenzyl, has been found to exert anticancer effects in multiple cancer cell types. In this study, we investigated the effect and mechanism of Riccardin D on human breast cancer. Experiments were performed on human breast cancer MCF-7 and MDA-MB-231 cells. The antitumour effects of Riccardin D were assessed by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and human breast cancer xenografts mice model. TRAPeze(®) XL Telomerase Detection assay was used for the detection of telomerase activity. γ-H2 AX foci formation was tested for the induction of DNA damage response. Cell cycle distribution was analysed by flow cytometry, and cell apoptosis was determined by annexin V-FITC/PI staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay and Western blotting. Riccardin D effectively inhibited the growth of MCF-7 and MDA-MB-231 cells in vitro. And Riccardin D also effectively delayed the growth of MCF-7 and MDA-MB-231-luc-D3H2LN xenografts without significant loss of body-weight. Further analysis suggested that Riccardin D's effects may arise from its suppression of telomerase activity, which led to telomere dysfunction. Telomerase inhibition and telomere dysfunction could activate the canonical ataxia telangiectasia-mutated (ATM) kinase-mediated DNA damage response, as shown by elevated expression of γ-H2 AX, p-ATM and p-Chk2. This is finally followed by the induction of cell cycle arrest and apoptosis, as shown by the increase of TUNEL-stained cells, caspase activation, PARP cleavage and the increase of bax/bcl-2 ratio. Moreover, Riccardin D induced p53-proficient MCF-7 cells to arrest in G1 phase and p53-deficient MDA-MB-231 cells to arrest in G2/M phase. Overall, these results demonstrate that Riccardin D may inhibit human breast cancer growth through suppression of telomerase activity.

Background Coadministration of 1,4-dihydropyridine calcium channel blockers (DHP-CCBs) with statins (or 3-hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase inhibitors) is common for patients with hypercholesterolemia and hypertension. To reduce the risk of myopathy, in 2011, the US Food and Drug Administration (FDA) Drug Safety Communication set a new dose limitation for simvastatin, for patients taking simvastatin concomitantly with amlodipine. However, there is no such dose limitation for atorvastatin for patients receiving amlodipine. The combination pill formulation of amlodipine/atorvastatin is available on the market. There been no systematic review of the pharmacokinetic drug–drug interaction (DDI) profile of DHP-CCBs with statins, the underlying mechanisms for DDIs of different degree, or the corresponding management of clinical risk. Methods The relevant literature was identified by performing a PubMed search, covering the period from January 1987 to September 2013. Studies in the field of drug metabolism and pharmacokinetics that described DDIs between DHP-CCB and statin or that directly compared the degree of DDIs associated with cytochrome P450 (CYP)3A4-metabolized statins or DHP-CCBs were included. The full text of each article was critically reviewed, and data interpretation was performed. Results There were three circumstances related to pharmacokinetic DDIs in the combined use of DHP-CCB and statin: 1) statin is comedicated as the precipitant drug (pravastatin–nimodipine and lovastatin–nicardipine); 2) statin is comedicated as the object drug (isradipine–lovastatin, lacidipine–simvastatin, amlodipine–simvastatin, benidipine-simvastatin, azelnidipine– simvastatin, lercanidipine–simvastatin, and amlodipine–atorvastatin); and 3) mutual interactions (lercanidipine–fluvastatin). Simvastatin has an extensive first-pass effect in the intestinal wall, whereas atorvastatin has a smaller intestinal first-pass effect. The interaction with simvastatin seems mainly driven by CYP3A4 inhibition at the intestinal level, whereas the interaction with atorvastatin is more due to hepatic CYP3A4 inhibition. The interaction of CYP3A4 inhibitor with simvastatin has been more pronounced compared with atorvastatin. From the current data, atorvastatin seems to be a safer CYP3A4-statin for comedication with DHP-CCB. There is no convincing evidence that amlodipine is an unusual DHP-CCB, either as a precipitant drug or as an object drug, from the perspective of CYP3A4-mediated drug metabolism. Amlodipine may have interactions with CYP3A5 in addition to CYP3A4, which may explain its particular characteristics in comparison with other DHP-CCBs. The degree of DDIs between the DHP-CCB and statin and the clinical outcome depends on many factors, such as the kind of statin, physicochemical proprieties of the DHP-CCB, the dose of either the precipitant drug or the object drug, the sex of the patient (eg, isradipine–lovastatin), route of drug administration (eg, oral versus intravenous nicardipine–lovastatin), the administration schedule (eg, nonconcurrent dosing method versus concurrent dosing method), and the pharmacogenetic status (eg, CYP3A5-nonexpressers versus CYP3A5-expressers). Conclusion Clinical professionals should enhance risk management regarding the combination use of two classes of drugs by increasing their awareness of the potential changes in therapeutic efficacy and adverse drug reactions, by rationally prescribing alternatives, by paying attention to dose adjustment and the administration schedule, and by review of the appropriateness of physician orders. Further study is needed – the DDIs between DHP-CCBs and statins have not all been studied in humans, from either a pharmacokinetic or a clinical perspective; also, the strength of the different pharmacokinetic interactions of DHP-CCBs with statins should be addressed by systematic investigations.

Two novel cyclotetrapeptides, tataricins A and B, with a unique cyclopeptide backbone and a (Delta) (2,4)Pro side chain, were isolated from the traditional Chinese medicine Aster tataricus. Their structures and absolute configurations were determined using a combination of spectroscopic data, the advanced Marfey's method, and a total synthesis. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.

Monte Carlo method and the Fuller curve are used to calculate the amount of the aggregate of concrete. The programmer of generating mesoscopic concrete is written to simulate the cracking evolution through two-dimensional plane. In the mesoscopic concrete, the sample is described by a Tri-phase material which consists of aggregate, matrices and interface. Based on the model， a study on how the cracks generate, develop and cut through in the concrete. The results show that: the interface is the vulnerable part of the concrete, the determination of the parameter and the damage criterion of the interface element is the governing factor. During the cracking evolution, the interface element destroyed firstly, and then the crack expense along the edge of the aggregates, cutting through the concrete and damaged finally. Numerical simulation of mesoscopic concrete cracking evolution can be used to understand and describe the damage style and strength characters.

Based on the equation analysis method and theorem dimensional analysis, the scaling rules between field tests and mode tests for embedded suction anchors have been investigated. Some critical parameters affecting the characteristics of anchor penetration and capacity are studied in detail. It is illustrated that although adopting non-normal scale because of using prototype of soil and water in model tests, the model tests could reflect the qualitative nature in field tests through adjusting some critical scale factors.

Conical valve’s spool-seat contact pairs is consisted of two surfaces of different curvature radius, and form closed circular contact line. It can be considered as the model of elastic hemi-space contact by the Hertz Theory. The numerical simulation and experiment show: The model is suitable for the analysis of conical valve’s spool-seat contact pairs. The conical valve’ sealing performance is very credible and its performance is very good. Maximum stress is smaller than allowable stress of the seat’s material. The consistency of experiment and simulation proves the validity and practicability of the hemi-space contact model of the valve’s spool-seat contact pairs.