Growth behavior of iron(II) phthalocyanine (FePc) molecules on Au(111) surface at the initial stage is studied with low-temperature scanning tunneling microscopy. The FePc molecules are separately adsorbed on the face-centered cubic and the hexagonal close-packed regions at the submonolayer regime, indicating that the molecular adsorption is greatly affected by the molecule−substrate interaction. At the monolayer regime, the molecules can form a close-packed ordered structure. When the FePc goes further to the second layer, the unit cell of the formed molecular superstructure shifts compared with the unit cell of the first layer. Comparison of the growth behavior between the FePc and the CoPc also is made to understand the growth difference within the family of the phthalocyanine (Pc) molecules. And it is found that the central metal atom of the metal Pc makes a main contribution to the shift. Our results are helpful for understanding the growth of the Pc molecule family and controlling the related physical properties.

We use low energy electron diffraction, scanning tunneling microscopy, first-principles densityfunctional theory, and molecular mechanics calculations to analyze the adsorption and growth of quinacridone derivatives (QA) with alkyl chains of 4 and 16 carbon atoms on a Ag(110) substrate. Surprisingly, we find that the alkyl chains determine the orientation of the molecular overlayers. While the interaction of QA and the Ag substrate is primarily due to chemical bonding of oxygen to the silver substrate, determining the molecular orientation and preferred adsorption site, the intermolecular arrangement can be adjusted via the length of alkyl chains. We are thus able to fabricate uniform QA films with very well controlled physical properties. DOI: 10.1103/PhysRevLett.96.226101 PACS numbers: 81.07.Nb, 68.43.ÿh, 81.16.Dn In recent years, the structure and growth of functional molecular thin films have been widely investigated due to their potential application for molecular devices [1][2][3][4]. However, understanding the interactions between organic molecules and noble metal substrates is not straightforward and has proven to be rather challenging [1][2][3][4][5]. In this respect, the ability to control the structure of molecular thin films provides a method of tuning the functional properties in a discrete manner. Previous work demonstrated that linear aromatic hydrocarbons attach to a silver substrate via interactions of the lowest unoccupied molecular orbital (LUMO) and silver 4d orbitals [6]. The match of the LUMO and the silver 4d orbitals also dominates the structural properties of the ensuing molecular film. Subsequent work concerned the lateral functional groups interacting with silver substrates, such as CN and CO groups in DMe-DCNQI and PTCDA [7]. The work suggested that the adsorbate-substrate geometry of large aromatic molecules on noble metal surfaces can be precisely controlled by functional groups of the molecule. However, the intermolecular geometry is less well researched due to lack of experimental data. Correspondingly, the understanding of intermolecular interaction is still somewhat shallow.For example, quinacridone and its derivatives (QA) are well-known chemically stable pigments. They display excellent photovoltaic and photoconductive properties [8][9][10]. The performance of organic light emitting devices based on QA have been widely investigated [11][12][13][14]. The QA molecular structure can be varied by the substitution of C atoms by N and O. QA can also be modified by attaching lateral alkyl chains to N heteroatoms and by the formation of QAnC, as shown in Fig. 1(a), where n denotes the number of carbon atoms in each alkyl chain. Accordingly, the photoelectric or electrical property can be adjusted by structural alterations of the molecule. It is quite possible that the lateral alkyl chains act as spacers and modulate the intermolecular distance. In this case the energy transfer between QAnC functional units is modified by noncovalent interactions between molecules, which are tuned ...

Recent studies have demonstrated that formaldehyde (FA)—induced neurotoxicity is important in the pathogenesis of Alzheimer's disease (AD). Elevated levels of FA have been associated with memory impairments and the main hallmarks of AD pathology, including β-amyloid plaques, tau protein hyperphosphorylation, and neuronal loss. Resveratrol (Res), as a polyphenol anti-oxidant, has been considered to have therapeutic potential for the treatment of AD. However, it has not been elucidated whether Res can exert its neuroprotective effects against FA-induced neuronal damages related to AD pathology. To answer this question, the effects of Res were investigated on Neuro-2a (N2a) cells prior to and after FA exposure. The experiments found that pre-treatment with Res significantly decreased FA-induced cytotoxicity, reduced cell apoptosis rates, and inhibited the hyperphosphorylation of tau protein at Thr181 in a dose-dependent manner. Further tests revealed that this effect was associated with the suppression of glycogen synthase kinase (GSK-3β) and calmodulin-dependent protein kinase II (CaMKII) activities, both of which are important kinases for tau protein hyperphosphorylation. In addition, Res was found to increase the activity of phosphoseryl/phosphothreonyl protein phosphatase-2A (PP2A). In summary, these findings provide evidence that Res protects N2a cells from FA-induced damages and suggests that inhibition of GSK-3β and CaMKII and the activation of PP2A by Res protect against the hyperphosphorylation and/or mediates the dephosphorylation of tau protein, respectively. These possible mechanisms underlying the neuroprotective effects of Res against FA-induced damages provide another perspective on AD treatment via inhibition of tau protein hyperhosphorylation.

FA was found to induce major AD-like pathological markers and cognitive impairments in young rhesus monkeys independent of genetic predispositions. This suggests FA may play a significant role in the initiation and progression of the disease.

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BACKGROUND AND PURPOSE3-Hydroxy-octanoate, recently identified as a ligand for, the orphan GPCR, HCA3, is of particular interest given its ability to treat lipid disorders and atherosclerosis. Here we demonstrate the pathway of HCA3-mediated activation of ERK1/2. EXPERIMENTAL APPROACHUsing CHO-K1 cells stably expressing HCA3 receptors and A431 cells, a human epidermoid cell line with high levels of endogenous expression of functional HCA3 receptors, HCA3-mediated activation of ERK1/2 was measured by Western blot. KEY RESULTSHCA3-mediated activation of ERK1/2 was rapid, peaking at 5 min, and was Pertussis toxin sensitive. Our data, obtained by time course analyses in combination with different kinase inhibitors, demonstrated that on agonist stimulation, HCA3 receptors evoked ERK1/2 activation via two distinct pathways, the PLC/PKC pathway at early time points (Յ2 min) and the MMP/ epidermal growth factor receptor (EGFR) transactivation pathway with a maximum response at 5 min. Furthermore, our present results also indicated that the bg-subunits of the Gi protein play a critical role in HCA3-activated ERK1/2 phosphorylation, whereas b-arrestins and Src were not required for ERK1/2 activation. CONCLUSIONS AND IMPLICATIONSWe have described the molecular mechanisms underlying the coupling of human HCA3 receptors to the ERK1/2 MAP kinase pathway in CHO-K1 and A431 cells, which implicate the Gi protein-initiated, PLC/PKC-and platelet-derived growth factor receptor/EGFR transactivation-dependent pathways. These observations may provide new insights into the pharmacological effects and the physiological functions modulated by the HCA3-mediated activation of ERK1/2. AbbreviationsADAM, a disintegrin and metalloproteinase; CRE, cAMP response element; EGFR, epidermal growth factor receptor;

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A: Intergroup analyses of Aβ 40 concentrations. B: Intergroup analyses of Aβ 42 concentrations. C: Intergroup analyses of FA concentrations. D: Correlation between CSF Aβ 40 and FA concentrations in young group ( R =–0.3385, P =0.2172). E: Correlation between CSF Aβ 40 and FA concentrations in middle-aged group ( R =0.02914, P =0.8976). F: Correlation between CSF Aβ 40 and FA concentrations in aged group ( R =–0.5318, P =0.0158). G: Correlation between CSF Aβ 42 and FA concentrations in young group ( R =–0.379, P =0.1635). H: Correlation between CSF Aβ 42 and FA concentrations in middle-aged group ( R =0.4296, P =0.046). I: Correlation between CSF Aβ 42 and FA concentrations in aged group ( R =–0.5344, P =0.0184). Error bars indicate mean± standard deviation ( SD ). *: P <0.05, **: P <0.01, ***: P <0.001. Aβ: β-amyloid; CSF: Cerebrospinal fluid.