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(Coumarin‐4‐yl)methyl (c4m) and p‐hydroxyphenacyl (pHP)‐based compounds are well known for their highly efficient photoreactions, but often show limited solubility in aqueous media. To circumvent this, we synthesized and characterized the two new c4m and pHP‐based photoacid generators (PAGs), 7‐[bis(carboxymethyl)amino]‐4‐(acetoxymethyl)coumarin (c4m‐ac) and p‐hydroxyphenacyl‐2,5,8,11‐tetraoxatridecan‐13‐oate (pHP‐t), and determined their solubilities, stabilities and photolysis in aqueous media. The two compounds showed high solubilities in water of 2.77 mmol L−1±0.07 mmol L−1 (c4m‐ac) and 124.66 mmol L−1±2.1 mmol L−1 (pHP‐t). In basic conditions at pH 9, solubility increased for c4m‐ac to 646.46 mmol L−1±0.63 mmol L−1, for pHP‐t it decreased to 34.68 mmol L−1±0.62 mmol L−1. Photochemical properties of the two PAGs, such as the absorption maxima, the maximum molar absorption coefficients and the quantum yields, were found to be strongly pH‐dependent. Both PAGs showed high stabilities s24h ≥95 % in water for 24 h, but decreasing stability with increasing pH value due to hydrolysis. The present study contributes to a clearer insight into the synthesis, solubilities, stabilities, and photolysis of c4m and pHP‐based PAGs for further photochemical applications when high PAG concentrations are required, such as in polymeric foaming.
Stability maintenance at the grassroots: China’s weiwen apparatus as a form of conflict resolution
(2013)
This working paper explores the history and potential of “stability maintenance” (weiwen) as a form of conflict resolution in China. Its emphasis on conflict resolution is novel. Previous examinations of the weiwen apparatus have concentrated on its political function, namely to manage resistance within society and maintain the authority of the party-state. This avenue of investigation has proved fruitful as a means of characterising the political motivation and the higher-level strategies involved in stability maintenance. Nonetheless, there remain significant conceptual and empirical gaps relating to how stability maintenance offices and processes actually function, particularly out of larger cities and at local levels. The research described in this paper aims to consider the effectiveness of stability maintenance as a part of the “market” for conflict resolution in local China, and to test the hypothesis that conflict resolution as facilitated by weiwen is the most pragmatic and effective means of actually resolving conflicts in the current Chinese political context, notwithstanding the closeness of the stability maintenance discourse to state authority and its relative distance from rule of law-based methods of dispute resolution...
The development of tractable forward looking models of monetary policy has lead to an explosion of research on the implications of adopting Taylor-type interest rate rules. Indeterminacies have been found to arise for some specifications of the interest rate rule, raising the possibility of inefficient fluctuations due to the dependence of expectations on extraneous "sunspots ". Separately, recent work by a number of authors has shown that sunspot equilibria previously thought to be unstable under private agent learning can in some cases be stable when the observed sunspot has a suitable time series structure. In this paper we generalize the "common factor "technique, used in this analysis, to examine standard monetary models that combine forward looking expectations and predetermined variables. We consider a variety of specifications that incorporate both lagged and expected inflation in the Phillips Curve, and both expected inflation and inertial elements in the policy rule. We find that some policy rules can indeed lead to learnable sunspot solutions and we investigate the conditions under which this phenomenon arises.
The role of endogenous melatonin for the control of the circadian system under entrained conditions and for the determination of the chronotype is still poorly understood. Mice with deletions in the melatoninergic system (melatonin deficiency or the lack of melatonin receptors, respectively) do not display any obvious defects in either their spontaneous (circadian) or entrained (diurnal) rhythmic behavior. However, there are effects that can be detected by analyzing the periodicity of the locomotor behaviors in some detail. We found that melatonin-deficient mice (C57Bl), as well as melatonin-proficient C3H mice that lack the melatonin receptors (MT) 1 and 2 (C3H MT1,2 KO), reproduce their diurnal locomotor rhythms with significantly less accuracy than mice with an intact melatoninergic system. However, their respective chronotypes remained unaltered. These results show that one function of the endogenous melatoninergic system might be to stabilize internal rhythms under conditions of a steady entrainment, while it has no effects on the chronotype.
Brain-derived neurotrophic factor (BDNF), an important neural growth factor, has gained growing interest in neuroscience, but many influencing physiological and analytical aspects still remain unclear. In this study we assessed the impact of storage time at room temperature, repeated freeze/thaw cycles, and storage at −80 °C up to 6 months on serum and ethylenediaminetetraacetic acid (EDTA)-plasma BDNF. Furthermore, we assessed correlations of serum and plasma BDNF concentrations in two independent sets of samples. Coefficients of variations (CVs) for serum BDNF concentrations were significantly lower than CVs of plasma concentrations (n = 245, p = 0.006). Mean serum and plasma concentrations at all analyzed time points remained within the acceptable change limit of the inter-assay precision as declared by the manufacturer. Serum and plasma BDNF concentrations correlated positively in both sets of samples and at all analyzed time points of the stability assessment (r = 0.455 to rs = 0.596; p < 0.004). In summary, when considering the acceptable change limit, BDNF was stable in serum and in EDTA-plasma up to 6 months. Due to a higher reliability, we suggest favoring serum over EDTA-plasma for future experiments assessing peripheral BDNF concentrations.
Electromagnetic calorimeter (ECAL) is being developed to complement dilepton spectrometer HADES. ECAL will enable the HADES@FAIR experiment to measure data on neutral meson production in heavy ion collisions at the energy range of 2-10 AGeV on the beam of future accelerator SIS100@FAIR. We will report results of the last beam test with quasi-monoenergetic photons carried out in MAMI facility at Johannes Gutenberg Universität Mainz.