Influence of sodium fluoride on alkaline phosphatase activity and bone gla protein synthesis in human yellow ligament cells in vitro

Objective To investigate the influence of sodium fluoride(NaF)on alkaline phosphatase(ALP)activity and bone gla protein(BGP)synthesis in yellow ligament cells from different surgical simples in vitro.Methods The human ligament cells

Non-equilibrium and stochasticity influence the activation process of the yeast DNA damage pathway

Living cells are open systems that exist far away from a state of thermodynamical equilibrium.They utilize the high-grade chemical energy provided by food to produce ATP and release ADP and Pi together with heat dissipation.Living cells exist in a non-equilibrium steady state(NESS),they replicate themselves and respond to various environmental changes

The influence of HDL and purified apoprotein E on platelet activation induced by serotonin

Elevated plasma levels of high density lipoprotein (HDL) are recognized as having a beneficial influence on the progression of atherosclerosis. As platelets are closely involved in atherosclerogenesis, it is difficult to evaluate if the protective effect of HDL is associated with its ability to affect platelet structure and function. Previous studies give conflicting reports concerning the HDL platelet interaction. In our in vitro experiments, washed human blood platelets were preincubated with HDL (100 800 μg/ml) and then stimulated by serotonin (5 Hydroxytryptamine, 1 5 μM), a potent agonist and mediator in the process of atherosclerosis. Aggregatory studies and electron microscopy revealed that HDL could not prevent morphological alterations of blood platelets treated with serotonin. Furthermore, high dosages of HDL led to platelet activation. These findings indicate that HDL may not inhibit agonist induced platelet activation. As HDL is a heterogeneous group of different subclasses with opposite effects on platelet function, it Platelet Research Unit, Institute of Anatomy, University of Münster, Germany (Pfennig O and Dierichs R) Institute of Physiology, Ruhr University Bochum, Bochum, Germany (Liu B) can be concluded that HDL platelet interaction reflects relative concentrations of the particular sample. Our findings suggest that the protective influence of HDL may not be associated with decreased platelet function. Apoprotein E rich subclasses of HDL (HDL 2), particularly HDL enriched apoprotein E (HDL E), inhibit agonist induced platelet activation. In order to enlighten the role of apo E in this process, platelets in suspensions were preincubated with purified apoprotein E (50 400 μg/ml) and then stimulated by serotonin (5 μM). Apoprotein E of 300 μg/ml prevented morphological alterations of blood platelets and suppressed serotonin induced activation. Lower concentrated apoprotein E showed no clear effects. There is evidence that apoprotein E is an important factor in the prevention of atherosclerosis, by enhancing the reversed cholesterol transport to the liver and modifiing the functional status of different cell types such as macrophages and smooth muscle cells. Because results showed effects of apo R on platelet activation, we suggest that apoprotein E may be a principal factor when platelet aggregability is suppressed by HDL subclasses or liposomes and that the antiatherogenic potency of apo E correlates with this process.

The influence of desiccation on the recovery process of nitrogenase activity in restored biological soil crusts

Dear Editor,Biological soil crusts(BSCs),a layered structure formed by associations of soil organisms and topsoil,dominate arid and semiarid areas and serve important ecological functions in these areas(Eldridge and Greene,1994).Nitrogen fixation by BSCs is the main source of N in arid and semi-arid ecosystems.Desiccation is the most notable factor that influences BSCs,which recover physiological activity only after moistening.By influencing the amount of carbohydrates,

Joint model of user check-in activities for point-of-interest recommendation

With the rapid development of location-based networks, point-of-interest（POI） recommendation has become an important means to help people discover interesting and attractive locations, especially when users travel out of town. However, because users only check-in interaction is highly sparse, which creates a big challenge for POI recommendation. To tackle this challenge, we propose a joint probabilistic generative model called geographical temporal social content popularity（GTSCP） to imitate user check-in activities in a process of decision making, which effectively integrates the geographical influence, temporal effect, social correlation, content information and popularity impact factors to overcome the data sparsity, especially for out-of-town users. Our proposed the GTSCP supports two recommendation scenarios in a joint model, i.e., home-town recommendation and out-of-town recommendation. Experimental results show that GTSCP achieves significantly superior recommendation quality compared to other state-of-the-art POI recommendation techniques.