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Palladium-catalyzed cross-coupling of ortho-alkenyl bromobenzenes and α-aryl-α-diazoesters was realized. The reactions proceeded in moderate to excellent yields with broad substrate scope, providing a straightforward method for the synthesis of 1,1-disubstituted indenes. The reaction is thought to undergo a tandem alkenyl C–H activation/carbene insertion sequence, in which a C,C-pallada(II)cycle is the key intermediate.

The amine submetabolome, including amino acids (AAs) and biogenic amines (BAs), is a class of small molecular compounds exhibiting important physiological activities. Here, a new pyrylium salt named 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate ([

A palladium-catalyzed intermolecular cross-coupling of unreactive C(sp3)–H bonds and azole C(sp2)–H bonds with bromide as a traceless directing group is described.

1,4-Palladium migration has emerged as a reliable method for directed C-H functionalization. In contrast to coupling with carbon nucleophiles, limited examples with heteroatom nucleophiles have been reported. Herein we report a palladium-catalyzed intermolecular C(sp

Endogenous guanidino compounds (GCs), nitrogen-containing metabolites, have very important physiological activities and participate in biochemical processes. Therefore, accurately characterizing the distribution of endogenous GCs and monitoring their concentration variations are of great significance. In this work, a new derivatization reagent, 4,4'-bis[3-(dimethylamino)propyl]benzyl (BDMAPB), with isotope-coded reagents was designed and synthesized for doubly charged labeling of GCs. BDMAPB-derivatized GCs not only promote the MS signal but also form multicharged quasimolecular ions and abundant fragment ions. With this reagent, an isotope-coded doubly charged labeling (ICDCL) strategy was developed for endogenous GCs with high-resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF MS). The core of this methodology is a 4-fold multiplexed set of [

Three new recorded species of genus

A third species of the genus Sinhomidia is described from South China: S. unisetasp. nov. This new species can be distinguished from the two other species of the genus by the following characters: colour pattern, single labial chaeta M, chaetotaxy on terga and ventral tube, unguis with three inner teeth, and 15 clypeal ciliated chaetae. Also, the chaetotaxy of the first instar of Sinhomidia is described for the first time in the present paper, and confirms the close relationship between Sinhomidia and Homidia. A key to species of Sinhomidia is provided.

A highly efficient palladium-catalyzed cross-coupling of 2,2-diarylvinyl bromides with diazo compounds was developed, providing a convenient approach for the synthesis of tetrasubsti-tuted allenes. Both aryl diazo carbonyl compounds and N-tosylhydrazones are competent carbene precursors in this reaction. An unprecedented hydrogen elimination of the π-allyl palladium intermediate is proposed to be the key step.

A Zn-mediated propargylation/lactamization cascade reaction with chiral 2-formylbenzoate derived N-tert-butanesulfinyl imines was realized, which provided a practical and efficient method for the synthesis of chiral isoindolinones. High diastereoselectivities (up to 97:3 dr) and good reaction yields were observed for most examined cases.

The first Ni-catalyzed ortho-sulfonylation of C(sp2)–H bonds with sodium sulfinates directed by (pyridin-2-yl)isopropylamine (PIP-amine) is described. This strategy exhibits a broad substrate scope and good functional group tolerance with high monosulfonylation selectivity. Besides arenes and heteroarenes, the reaction can also be extended to alkenes, providing diverse diaryl and alkyl-aryl sulfones in high yields. Furthermore, a plausible Ni(I)/Ni(III) mechanism is outlined based on our experimental results and related precedents.

The asymmetric rhodium-catalyzed alkenylation of enones and imines with arylboronic acids has been developed. A highly controllable aryl to vinyl 1,4-rhodium migration is the key step. Stereodefined vinyl moieties were installed in excellent enantioselectivies for most examined examples. DFT calculations reveal that the driving force of this rhodium migration is a kinetically favored process.

This article analyzes the bifucate Y-type coronary artery based on hemodynamics and computational fluid dynamics to study the optimal location for thrombosis. Mathematical derivation is used to analyze the fluid machanics. The issue of fully developed flow is derivated. The optimal location for thrombus is identified. According to the mathematical derivation and numerical modeling results, the optimal location for thrombus is at the bifurcation of coronary artery. Vortex and turbulent fluctuation will take place. Three bifurcate angle (60, 90 and 120) is chosen to analyze by numarical stimulation. The result shows that vortex at bifurcation area grows when the bifrucate angle increases. It may cause the sediment of blood platelet, fibrous protein and lipochondrion [1]. It is also concluded that the wall shear stress is so high that it may injure the vascular wall around bifurcation.

In the current study, simulations based on the engineering equation solver (EES) software are performed to determine the suitable working fluid for the simple organic Rankine cycle system in different temperature ranges. Under the condition of various temperatures and a constant thermal power of the flue gas, the influence of different organic working fluids on the efficiency of the subcritical organic Rankine cycle power generation system is studied, and its efficiency and other parameters are compared with those of the regenerator system. It is shown that the efficiency of the subcritical organic Rankine cycle system is the best when the parameters of the working fluid in the expander inlet are in the saturation state. And for the organic Rankine cycle, the R245fa is better than other working fluids and the efficiency of the system reaches up to 10.2% when the flammability, the toxicity, the ozone depletion, the greenhouse effect and other factors of the working fluids are considered. The R601a working fluid can be used for the high-temperature heat source, however, because of its high flammability, new working fluid should be investigated. Under the same condition, the efficiency of the organic Rankine cycle power generation system with an internal heat exchanger is higher than that of the simple system without the internal heat exchanger, but the efficiency is related to the properties of the working fluid and the temperature of the heat source.

By accident of a power plant desulfurization CFD Research sprinkler system model to simulate the process of considering the two-way coupling between the droplet atomization, evaporation, with the main flue gas stream. The results showed that x = 3300 sectional arrangement 40 nozzles, high temperature flue gas through a water spray after 10.8m reach x = 14100 section of the temperature has dropped to 358K, before entering the GGH down to 345K, meet an accident situation spray cooling requirements.

This paper describes the composition and working principle of aircraft parts flexible automatic assembly platform, and gives the detailed analysis and design of flexible automatic assembly platform of mechanical structure and motion adjusting control system. The two types of multi plane assembly shows that automatic assembly platform automatic adjusting is reliable, operation control system and motion mechanism runs stable, this system can meet the various needs of automatic assembly platform of aircraft components, and it realizes the work mode of assembly and products in one to many during the aircraft components Assembly process.

A hybrid graph and rule-based method for recognizing machining features is proposed in this paper, which aims to get the machining feature in 3D in-process model construction system. Initially, the attributed adjacency graph (AAG) of the input MBD models is constructed and represented in matrix form. After that, by deleting the convex edges of the AAG, the concave sub-graphs are generated. For obtaining the volumetric features, their concave sub-graphs are matched with the feature template graphs in a pre-defined library; for those which can be generated by sweeping the edge loops, such as open pocket, closed pocket, through pocket and slot, their features are recognized by using rules. In experimental section, an example is given to illustrate the validity and effectiveness of the proposed method.

A new photoelectrochemical (PEC) biosensor was developed using low-toxic Ag2S QDs as photoelectrochemically active species. Energy levels of Ag2S and Ag2Se QD were compared to explain their differences in the PEC performance. The preparation condition of Ag2S QD was optimized and its structure characterization was measured. Then the developed photoelectric active interface was used to detect glucose and MCF-7 cancer cell and showed the good sensitivity and specificity. Under optimal condition, detection limits of 3.2 × 10(-5)M for glucose and 98 cells/mL for MCF-7 cell were achieved. Thus, the prepared Ag2S QD could serve as an excellent and promising photoelectric active material in the PEC biosensor.

This paper describes the measurement of the parameters of the experiment, the problems in the analysis of experimental data processing and experimental error. The flow pattern and pressure drop of flow boiling, heat flux and heat transfer coefficient of relations are studied by analysis of the experimental data. The test section were isolated three flow patterns, bubble-like flow, limited bubble-like flow and evaporated to dryness district. Only isolated bubble-like flow of a stream type such as channel width = 2.0mm thin channel, volume flow greater than 15.47L/h. For channel width =1.0mm thin channel, bubbly flows is limited bubbly flow changes corresponding volume flow 10.8L/h.

To further deepen exploration of boiling in micro-channels a set of experiment system for micro-channel flow boiling is homemade, which includes experimental equipment required and experimental pieces of the design process. The channel is width of 100mm, length of 1200mm, and the groove depth of 95mm. The gasket thickness is 0.5mm, 1.0mm, 1.5mm or 2.0mm.

To reduce the workload for marking the dimensions of in-process models, a method of dimension marking based on manufacturing features for in-process model is proposed. Firstly, the dimension information is extracted from model based definition (MBD) models; secondly, the feature dimension chains are constructed according to the feature location dimension and the process data, when the process data and design data are not coincided with each other; thirdly, the process dimension tolerances are calculated by using the increasing links and the decreasing links of the MBD. In experimental section, an example was given to illustrate the validity and effectiveness of the proposed method.

Technologies that use surface-enhanced Raman scattering (SERS) have experienced significant growth in biomedical research during the past four years. SERS signal amplification based on enzyme action recently attracted considerable attention due to the need for ultrasensitive bioassays and the trend towards miniaturized assays. This review highlights recent developments in SERS signal-amplification techniques based on enzyme action for cancer-biomarker detection, including multiplexed detection and identification of DNA, single-nucleotide polymorphisms, small bioactive molecules, protein, and tumor cells.

Coal mine is a dangerous place in which many fatal factors menace miners' life. When some disasters occur, it may be very dangerous for rescuers to go into mine tunnels to search survivors. So developing the coal mine detecting and rescue robot for mine rescue has a very important meaning. In this paper, a system of explosion-proof detecting robot is presented. The structure design methods of robot have been discussed in detail, including robot body, computer control system, explosion-proof and waterproof design of systems, mobile mechanism design and software design. Finally the application results are given.

For the demand of coal mine flood accident emergency rescue, in this paper, a mine-used underwater explosion-proof robot is presented and the composition structure and design method of the robot are discussed in detail. This device combines mechanical design, underwater power plant, intelligent control, energy supply of mobile device and mine explosion-proof technology. It can cruise underwater with the changeable depth, orientation and speed. It can move flexibly and can collect underwater and overwater images. Practical application shows that this equipment is suitable for the emergency rescue and disaster relief work after the coal mine flood.

The complete mitochondrial genome of Isonychia kiangsinensis is a circular molecule of 15,456 bp in length, containing 2 rRNA genes, 13 protein-coding genes, 22 tRNA genes, and a control region. Th...

The mitochondrial genome of Epeorus herklotsi (Ephemeroptera: Heptageniidae) is a circular molecule of 15,801 bp in length with a base composition of 32.7% A, 32.9% T, 21.5% C, 13.0% G, including extra tRNAMet gene. The IMQM tRNA cluster is found in E. herklotsi as well as Parafornuru youi and two species of Epeorus (KM244708, KJ493406), while the typical IQM tRNA cluster is found in Paegniodes cupulatus. In BI and ML phylogenetic trees, the monophyly of the families Heptageniidae, Baetidae, and Ephemerellidae are highly supported. E. herklotsi is a sister clade to Epeorus sp2. (KJ493406).

In the present study, a gold nanoparticle-modified gold electrode (nanogold electrode) was used to develop a novel fluorescein electrochemical DNA biosensor based on a target-induced conformational change. The nanogold electrode was obtained by electrodepositing gold nanoparticles onto a bare gold electrode. This modification not only immobilized probe oligonucleotides, but also adsorbed fluorescein onto the surface of the gold nanoparticles to form an “arch-like” structure. This article compares the electrochemical signal changes caused by the hybridization of “arch-like” DNA on nanogold electrode and linear DNA on bare gold electrode. The results showed that the adsorption effect of nanogold can enhance the sensitivity of the sensor. The linear range of target ssDNA is from 2.0 × 10 −9 M to 2.0 × 10 −8 M with a correlation coefficient of 0.9956 and detection limit (3 σ ) of 7.10 × 10 −10 M. Additionally, the specificity and hybridization response of this simple sensor were investigated.