Statistical properties of the rovibrational bound levels for Ar2Kr.

We calculate the rovibrational bound levels with total angular momentum J = 0, 1 of 40Ar284Kr trimer using the slow variable discretization method combined with the finite-element method-discrete variable representation basis. The statistical distributions of the rovibrational levels for JΠ=0e, 1e, and 1o symmetries are presented and the effects of the Axilrod-Teller potential term are considered. For the 0e and 1e symmetries, the Axilrod-Teller term makes the spectra become fully chaotic. However, for the 1o symmetry, statistical properties depend mainly on the coupling between K = 0 and K = 1 and the Axilrod-Teller term has a small effect.

[Influencing Factors on the Degradation of PFOS Through VUV-SO32].

The objective of this experiment was to investigate the influence of SO32-dosage, pH value, initial perfluorooctane sulfonate(PFOS)concentration as well as coexisting substances on the degradation and defluorination of PFOS by VUV-SO32- process. The results indicated that the increase of SO32- dosage could lead to rise in the concentration of active species hydrated electron(eaq-) and thus enhance the degradation and defluorination of PFOS. As the concentration of SO32- increased from 1 mmol·L-1 to 20 mmol·L-1, the degradation and defluorination rates of PFOS increased from 45% and 40% to 97% and 63%, respectively. The degradation and defluorination of PFOS were also enhanced with the increment of the solution pH values, and the defluorination was more sensitive to the pH values. In addition, more PFOS was degraded with the increase of initial PFOS mass concentration, although the degradation and defluorination rates of PFOS were reduced. When the initial PFOS mass concentration changed from 1 mg·L-1 to 50 mg·L-1, the degradation amount of PFOS after four hrs increased by about 50 times, probably due to the higher utilization proportion of eaq- at high pollutants concentration. Last but not least, the influence of co-existing substances, Cl- and HCO3-, on PFOS degradation could be neglected, whereas their effects on defluorination were observed. Defluorination of PFOS was enhanced with the increased Cl- concentration, however, increased first and then decreased with the increment of HCO3- concentration. It was also found that the presence of humic acid(HA) lowered degradation as well as defluorination of PFOS owing to the blockage of effective UV light and trapping of active species for photochemical reaction.

Hyperspherical coupled channel calculations of energy and structure of (4)He-(4)He-Li(+) and its isotopic combinations.

The ground state vibrational energy and spatial features of (4)He-(4)He-Li(+) and its triatomic isotopic complexes are studied using the slow variable discretization (SVD) method in the hyperspherical coordinates for the zero total angular momentum. Our results show that the dominant structure of the system is an isosceles triangle with the shorter side associated with the two Li(+)-He distances using the sum-of-potential approximation. Corrections caused by the induced dipole-induced dipole interactions on the He atoms are also investigated. The effects are seen to be small and have a minor influence on the binding energy and the structure of present system. The results are also compared with the full ab initio calculations including all the three-body interactions and information of three-body corrections is obtained.

7,8-dihydroxyflavone Ameliorates Motor Deficits Via Suppressing α-synuclein Expression and Oxidative Stress in the MPTP-induced Mouse Model of Parkinson's Disease.

BACKGROUND: Parkinson disease (PD) is a neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra (SN) and diminished dopamine content in the striatum, which is at least partly associated with α-synuclein protein overexpression in these neurons. Recent reports show that 7,8-dihydroxyflavone (DHF), a TrkB agonist, has beneficial effects in animal model of PD. However, it is unclear whether the therapeutic effects of DHF are associated with the expression of α-synuclein. AIMS: In this study, we investigated the protective effects of DHF on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced deficit of motor functions, the loss of dopaminergic neurons and the expression of α-synuclein as well as antioxidative activity in the C57BL/6 mice. RESULTS: Mice were treated with MPTP (30 mg/kg, i.p.) once a day for 5 days to induce dopaminergic neuron death in the SN. DHF (5 mg/kg, i.p.) was administrated once a day from the first day of MPTP injection until 9 days after the last injection of MPTP. Behavioral tests showed that DHF succeeded in ameliorating the impaired motor functions in the MPTP-treated mice. The immunohistochemical assay showed that the amelioration of motor function was accompanied by a reduction in the loss of dopaminergic neurons in the SN and striatum. Western blot analyses showed that DHF prevented the inactivation of TrkB and suppressed α-synuclein overexpression in the SN and striatum following MPTP treatment. Antioxidative activity detection revealed that DHF prevented MPTP-induced reduction in glutathione and total superoxide dismutase activity in the SN and striatum. CONCLUSION: Taken together, these results indicate that DHF treatment may suppress the accumulation of α-synuclein and oxidative stress via activating TrkB and subsequently block the loss of dopaminergic neurons in the SN and striatum, thereby ameliorating MPTP-induced motor deficits in the C57BL/6 mice.

Abnormal anxiety- and depression-like behaviors in mice lacking both central serotonergic neurons and pancreatic islet cells.

Dysfunction of central serotonin (5-HT) system has been proposed to be one of the underlying mechanisms for anxiety and depression, and the association of diabetes mellitus and psychiatric disorders has been noticed by the high prevalence of anxiety/depression in patients with diabetes mellitus. This promoted us to examine these behaviors in central 5-HT-deficient mice and those also suffering with diabetes mellitus. Mice lacking either 5-HT or central serotonergic neurons were generated by conditional deletion of Tph2 or Lmx1b respectively. Simultaneous depletion of both central serotonergic neurons and pancreatic islet cells was achieved by administration of diphtheria toxin (DT) in Pet1-Cre;Rosa26-DT receptor (DTR) mice. The central 5-HT-deficient mice showed reduced anxiety-like behaviors as they spent more time in and entered more often into the light box in the light/dark box test compared with controls; similar results were observed in the elevated plus maze test. However, they displayed no differences in the immobility time of the forced swimming and tail suspension tests suggesting normal depression-like behaviors in central 5-HT-deficient mice. As expected, DT-treated Pet1-Cre;Rosa26-DTR mice lacking both central serotonergic neurons and pancreatic islet endocrine cells exhibited several classic diabetic symptoms. Interestingly, they displayed increased anxiety-like behaviors but reduced immobility time in the forced swimming and tail suspension tests. Furthermore, the hippocampal neurogenesis was dramatically enhanced in these mice. These results suggest that the deficiency of central 5-HT may not be sufficient to induce anxiety/depression-like behaviors in mice, and the enhanced hippocampal neurogenesis may contribute to the altered depression-like behaviors in the 5-HT-deficient mice with diabetes. Our current investigation provides understanding the relationship between diabetes mellitus and psychiatric disorders.

The weakly bound states and resonances of the BeHe2 triatomic system.

In the present study, we carry out a full search of the bound states and resonances of the He(2)Be triatomic system, with its isotopic variants (3)He(2)(9)Be, (3)He(4)He(9)Be, and (4)He(2)(9)Be using the hyperspherical method. Three-body long-range effects are also included in the computation by adding to the additive potential the Axilrod-Teller triple-dipole term. In addition, the possibility of the occurrence of Efimov-type states in these systems is discussed. We have found a bound state for each of the (3)He(2)(9)Be and (3)He(4)He(9)Be trimers, while one weakly bound excited state is also found to exist for the (4)He(2)(9)Be system.

Enhanced contextual fear memory in central serotonin-deficient mice.

Central serotonin (5-HT) dysregulation contributes to the susceptibility for mental disorders, including depression, anxiety, and posttraumatic stress disorder, and learning and memory deficits. We report that the formation of hippocampus-dependent spatial memory is compromised, but the acquisition and retrieval of contextual fear memory are enhanced, in central 5-HT-deficient mice. Genetic deletion of serotonin in the brain was achieved by inactivating Lmx1b selectively in the raphe nuclei of the brainstem, resulting in a near-complete loss of 5-HT throughout the brain. These 5-HT-deficient mice exhibited no gross abnormality in brain structures and had normal locomotor activity. Spatial learning in the Morris water maze was unaffected, but the retrieval of spatial memory was impaired. In contrast, contextual fear learning and memory induced by foot-shock conditioning was markedly enhanced, but this enhancement could be prevented by intracerebroventricular administration of 5-HT. Foot shock impaired long-term potentiation and facilitated long-term depression in hippocampal slices in WT mice but had no effect in 5-HT-deficient mice. Furthermore, bath application of 5-HT in 5-HT-deficient mice restored foot shock-induced alterations of hippocampal synaptic plasticity. Thus, central 5-HT regulates hippocampus-dependent contextual fear memory, and 5-HT modulation of hippocampal synaptic plasticity may be the underlying mechanism. The enhanced fear memory in 5-HT-deficient mice supports the notion that 5-HT deficiency confers susceptibility to posttraumatic stress disorder in humans.

Binding energy and geometry of e+ A (A=Li,Na) by the hyperspherical approach.

We calculate the binding energy and geometry of the weakly bound e(+)Li and e(+)Na systems within the framework of hyperspherical coordinates. The Schrodinger equation in hyperangular coordinates is solved at a series of fixed hyper-radii using B-splines and the resulting coupled hyper-radial equation is solved using the slow variable discretization method developed by Tolstikhin et al. [J. Phys. B 29, L389 (1996)]. Great efforts are made in optimizing the distribution of B-splines to overcome the slow convergence of the binding energy and geometrical quantities. This approach allows us to obtain the results with improved convergence that are in good agreement with the best values reported to date. In addition, an analysis of the structure of the two systems is also made and the e(+)Na system is seen to exhibit quantum halo features.

Hyperspherical coupled channel calculations for the spectra and structure parameters of rare gas trimers NeAr2 and Ne2Ar.

We calculate the L=0 vibration energies and rotational constants for the van der Waals trimers 20NeAr2, 20Ne2Ar, and their corresponding isotopologues within the framework of hyperspherical coordinates. The Schrodinger equation in hyperangular coordinates is solved at a series of fixed hyper-radii using B-splines and the resulting coupled hyper-radial equation is solved using the slow variable discretization method developed by Tolstikhin et al. [J. Phys. B 29, L389 (1996)]. Using the special properties of B-splines, we make the knot distributions more precisely, characterizing the behavior of channel functions. Our method improves the convergence greatly. It turns out that our numerical tool works quite well in study of rare gas trimers. Calculations are performed on two kinds of pair potentials, the HFD-B and Tang-Toennies (TT) potentials, and the resultant rotational constants and their isotope shifts are compared with the experimental results obtained from high-resolution spectroscopy. The TT pair potentials give much better agreement with the experimental values for 20Ne2Ar and 22Ne2Ar trimers, while the HFD-B pair potentials give much better agreement with the experimental values for 20NeAr2 and 22NeAr2 trimers.

Exposure to chronic constant light impairs spatial memory and influences long-term depression in rats.

Exposure to chronic constant light (CCL) influences circadian rhythms and evokes stress. Since hippocampus is sensitive to stress, which facilitates long-term depression (LTD) in the hippocampal CA1 area, we examined whether CCL exposure influenced hippocampus-dependent spatial memory and synaptic plasticity in Wistar rats. Here we report that CCL exposure (3 weeks) disrupted 24-h cycle of locomotion activity in open field test. These rats showed shorter escape latency during initial phase of spatial learning but impaired hippocampus-dependent spatial memory without affecting the visual platform learning task in Morris water maze (MWM) compared with control rats. This effect may be due to stress adaptation as reflected by reduced thigmotaxis and anxiety-like behaviors in CCL rats. Moreover, in CA1 area of the hippocampal slices, CCL rats failed to show LTD by low frequency stimulation (LFS, 900 pulses, 1 Hz), while showed decreased short-term depression compared with control rats indicating the induction of LTD was influenced by CCL exposure. Furthermore, additional acute stress enabled LFS to induce LTD in control rats but not in CCL rats. Thus, these results suggested that CCL exposure impaired spatial memory and influenced hippocampal LTD, which may be due to stress adaptation.