Enantioselective Pd-catalyzed allylation of acyclic α-fluorinated ketones.

Significant synthetic challenges remain for the asymmetric synthesis of tertiary α-fluoro ketones, which are potentially useful molecules for the development of drugs, agrochemicals, and functional materials. Herein, we describe the development of a method for the catalytic enantioselective synthesis of tertiary α-fluoro ketones via the Tsuji-Trost reaction of racemic acyclic α-fluorinated ketones. Enantioenriched acyclic α-cabonyl tertiary fluorides can be produced with the aid of a palladium/phosphinooxazoline catalyst.

Organocatalytic reactions of α-trifluoromethylated esters with terminal alkenes at room temperature.

CF3-containing esters smoothly reacted with electron-deficient alkenes in the presence of a phosphine (2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl) organocatalyst at room temperature in an aerobic atmosphere. These Michael reactions efficiently provided products with a CF3 quaternary carbon center.

Precise Motion Control of a Power Line Inspection Robot Using Hybrid Time Delay and State Feedback Control.

Intelligent robotic inspection of power transmission lines has proved to be an excellent alternative to the traditional manual inspection methods, which are often tedious, expensive, and dangerous. However, to achieve effective automation of the robots under different working environments, the dynamic analysis and control of the robots need to be investigated for an efficient inspection process. Nonetheless, the application of control techniques for the position, speed and vibration control of these robots has not been explored in detail by the existing literature. Thus, an approach for precise motion control of the sliding inspection robot is presented in this paper. The main contribution of the study is that the chattering problem associated with the traditional command shaping time delay control (TDC) was minimized by smoothing the chattered input signal. Then, the improved control (iTDC) which is effective for oscillation control is hybridized with a pole placement based feedback control (PPC) to achieve both position and the sway angle control of the robot. The nonlinear and the linearized models of the sliding robot were established for the control design and analysis. Three parameters of the robot, namely, the length of the suspended arm, the mass of the payload, and the friction coefficient of different surfaces, were used to assess the robustness of the controller to model uncertainties. The iTDC + PPC has improved the velocity of TDC by 201% and minimizes the angular oscillation of PPC by 209%. Thus, the results demonstrate that the hybridized iTDC + PPC approach could be effectively applied for precise motion control of the sliding inspection robot.

Osteogenic protein-1 attenuates apoptosis and enhances matrix synthesis of nucleus pulposus cells under high-magnitude compression though inhibiting the p38 MAPK pathway.

BACKGROUND: Disc degeneration is correlated with mechanical load. Osteogenic protein-1 (OP-1) is potential to regenerate degenerative disc. OBJECTIVE: To investigate whether OP-1 can protect against high magitude compression-induced nucleus pulposus (NP) cell apoptosis and NP matrix catabolism, and its potential mechanism. METHODS: Porcine discs were cultured in a bioreactor and compressed at a relatively high-magnitude mechanical compression (1.3 MPa at a frequency of 1.0 Hz for 2 hours once per day) for 7 days. OP-1 was added along with the culture medium to investigate the protective effects of OP-1. NP cell apoptosis and matrix biosynthesis were evaluated. Additionally, activity of the p38 MAPK pathway is also analyzed. RESULTS: Compared with the control group, high magnitude compression significantly promoted NP cell apoptosis and decreased NP matrix biosynthesis, reflected by the increase in the number of TUNEL-positive cells and caspase-3 activity, the up-regulated expression of Bax and caspase-3 mRNA and down-regulated expression of Bcl-2 mRNA, and the decreased alcian blue staining intensity and expression of matrix proteins (aggrecan and collagen II). However, OP-1 addition partly attenuated the effects of high magnitude compression on NP cell apoptosis and NP matrix biosynthesis. Further analysis showed that inhibition of the p38 MAPK pathway partly participated in this process. CONCLUSION: OP-1 can attenuate high magnitude compression-induced NP cell apoptosis and promoted NP matrix biosynthesis, and inhibition of the p38 MAPK pathway may participate in this regulatory process. This study provides that OP-1 may be efficacy in retarding mechanical overloading-exacerbated disc degeneration.

[Effect of flying burthen on blood lipid in civil aviation aircrew].

OBJECTIVE: To investigate the effect of flying burthen on blood lipid level in civil aviation flight personnel. METHODS: The level of total cholesterol (TC), triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) were determined by kits. The relationship between the blood lipid levels and the flight personnel's flying hours, body weight index, smoking, drinking and sport were investigated. RESULTS: The average annual flying hours of hyperlipidemia group [(561.14 +/- 234.90) h] was significantly higher than that of non-hyperlipidemia group [(500.62 +/- 243.65) h] (P < 0.05). The level of TG of the average annual flying hours more 800 h [(1.61 +/- 0.10) mmol/L] were significantly higher than that of less than 400 h group [(1.31 +/- 0.65) mmol/L]. The morbidity rate of hyperlipidemia among the age 30 to 39 years old flight personnel was the highest. CONCLUSION: The average annual flying hours is one of primary factors affecting blood lipid in flight personnel.

Analysis of the mechanisms of rabbit's brainstem hemorrhage complicated with irritable changes in the alvine mucous membrane.

AIM: To explore the dynamic changes in the pressure of the lateral ventricle during acute brainstem hemorrhage and the changes of neural discharge of vagus nerve under the load of intracranial hypertension, so as to analyze their effects on the congestive degree of intestinal mucous membrane and the morphologic changes of intestinal mucous membrane. METHODS: An operation was made to open the skull to obtain an acute brainstem hemorrhage animal model. Microcirculatory microscope photography device and video recording system were used to determine the changes continuously in the caliber of jejunal mesenteric artery during brainstem hemorrhage and the changes with time in the congestion of jejunal mucosal villi. We used HE stain morphology to analyze the changes of duodenal mucosal villi. A recording electrode was used to calculate and measure the electric discharge activities of cervical vagus nerve. RESULTS: (1) We observed that the pressure of lateral cerebral ventricle increased transiently during acute brainstem hemorrhage; (2) The caliber of the jejunal mesenteric artery increased during brainstem hemorrhage. Analysis of red color coordinate values indicated transient increase in the congestion of jejunal mucous membrane during acute brainstem hemorrhage; (3) Through the analysis of the pathologic slice, we found enlarged blood vessels, stagnant blood, and transudatory red blood cells in the duodenal submucous layer; (4) Electric discharge of vagus nerve increased and sporadic hemorrhage spots occurred in duodenal mucous and submucous layer, when the lateral ventricle was under pressure. CONCLUSION: Brainstem hemorrhage could cause intracranial hypertension, which would increase the neural discharge of vagus nerve and cause the transient congestion of jejunal mucous membrane. It could cause hyperemia and diffused hemorrhage in the duodenal submucous layer 48 h after brainstem hemorrhage.

3-[3-(3-florophenyl-2-propyn-1-ylthio)-1, 2, 5-thiadiazol-4-yl]-1, 2, 5, 6-tetrahydro-1- methylpyridine oxalate, a novel xanomeline derivative, improves neural cells proliferation and survival in adult mice.

The present study analyzed the influence of 3-[3-(3-florophenyl-2-propyn-1-ylthio)-1, 2, 5-thiadiazol-4-yl]-1, 2, 5, 6-tetrahydro-1-methylpyridine oxalate (EUK1001), a novel xanomeline derivative of the M1/M4 receptor agonist, on hippocampal neurogenesis in adult C57BL6 mice. Results showed that 15-day EUK1001 treatment via intraperitoneal injection promoted neural cell proliferation in the dentate gyrus, although cell differentiation did not change. The majority of bromodeoxyuridine-positive cells co-expressed the immature neuronal marker doublecortin. In addition, the level of neurogenesis in the subventricular zone was not altered. Brain-derived neurotrophic factor mRNA expression was up-regulated following EUK1001 treatment, but no change was observed in expression of camp-responsive element binding protein 1, paired box gene 6, vascular endothelial growth factor alpha, neurogenic differentiation factor 1, and wingless-related mouse mammary tumor virus integration site 3A mRNA. These experimental findings indicated that EUK1001 enhanced proliferation and survival of hippocampal cells, possibly by increasing brain-derived neurotrophic factor expression.