336 research outputs found

    The value(s) of social media rituals: a cross-cultural analysis of New Year’s resolutions

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    © 2021 The Authors. Published by Routledge. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1080/1369118X.2021.1983003New Year’s resolutions are acts of valuation where people express ideas about what is important and worthwhile in life. Although resolutions have a long history, the twenty-first century has transformed the practice into a social media ritual with greater visibility, interactivity, and reach. Using this unique event to explore the globalization of values, we analyze tweets about New Year’s resolutions in English, German, Italian, Japanese, and Korean. Combining network analysis (n = 160,592) and content analysis (n = 2000), we compare discursive topics, modes of ritual participation, and the values expressed in resolutions. Our findings indicate both that the ritual crosses cultures and that there are language-specific dynamics that do not map neatly onto established divisions between ‘Eastern’ and ‘Western’ value orientations. Instead, we identify three underlying tensions organizing the articulation of values: self-acceptance vs. self-improvement, public vs. private, and conformity vs. oppositionality. We discuss these in relation to an overarching tension between local contexts and global platform cultures. Finally, we explore the study’s broader implications for understanding the interaction between values, norms, and global communicative practices.This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme [grant agreement No 819004].Published onlin

    Supported palladium nanoparticles as heterogeneous ligand-free catalysts for the Hiyama C C coupling of vinylsilanes and halobenzenes leading to styrenes

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    [EN] Palladium nanoparticles supported on magnesia is a highly efficient solid, reusable catalyst to promote in the absence of phosphine ligands the coupling of vinylsilanes with iodo- and bromobenzenes to form styrenes.Financial support by Spanish Ministry of Science and Innovation (Consolider MULTICAT and CTQ 2012-32316) is gratefully acknowledged. The Generalidad Valenciana is also thanked for partial financial support (Prometeo Grant).Grirrane, A.; García Gómez, H.; Corma Canós, A. (2013). Supported palladium nanoparticles as heterogeneous ligand-free catalysts for the Hiyama C C coupling of vinylsilanes and halobenzenes leading to styrenes. Journal of Catalysis. 302:49-57. doi:10.1016/j.jcat.2013.02.019S495730

    Synthesis of γ-ketocarboxylic acids via reduction of γ-keto-α-hydroxycarboxylic acids with carbon monoxide catalyzed by a PdHCl system

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    A PdHCl catalytic system is highly active in the synthesis of γ-ketoacids of type ArCOCH2CH2COOH via reduction with CO of the ketohydroxy acids ArCOCH2CHOHCOOH. Typical reaction conditions are: PCO: 20-30 atm; Pd/ substrate/H2O/HCl = 1/400-1000/800-3000/ 100-1000 (mol); temperature: 100-110°C; [Pd]: 10-3 to 10-2 M; solvent: dioxane; reaction time: 1-2 h. The reaction occurs in high yield only when the palladium precursor is used in combination with HCl and in the presence of H2O. Under the reaction conditions employed, the palladium(II) complex used as catalyst precursor decomposes to palladium metal. Pd/C is also highly active. It is proposed that the catalytic cycle proceeds through the following steps: (i) The chloride ArCOCH2CHClCOOH, which forms in situ from the starting substrate and HCl, undergoes oxidative addition to reduced palladium with formation of a catalytic intermediate having a Pd-[CH(COOH)CH2COPh] moiety. (ii) Interaction of H2O and CO on the metal yields an intermediate having also a carbohydroxy ligand, (HOOC)-Pd-[CH(COOH)CH2COPh]. (iii) This intermediate, after β-hydride abstraction from the carbohydroxy ligand, gives off CO2 and reductive elimination gives product PhCOCH2CH2COOH. Alternatively, HCl may react with the intermediate proposed in step (i), yielding directly the product and a Pd(II) species, which is reduced by CO to a Pd(0) species, which starts another catalytic cycle. © 1994

    Labeling of alprenolol with fluorescent aryl iodide as a reagent based on Mizoroki-Heck coupling reaction.

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    A novel fluorescent labeling method for alprenolol was developed based on Mizoroki-Heck coupling reaction. We designed and synthesized fluorescent aryl iodide, 4-(4,5-diphenyl-1H-imidazol-2-yl)iodobenzene (DIBI) as a labeling reagent. DIBI has a lophine skeleton carrying an iodide atom acting as fluorophore and reactive center, respectively. In order to evaluate the usefulness of DIBI, a high-performance liquid chromatography (HPLC) with fluorescence detection method was developed for the determination of alprenolol as a model compound of terminal double bond. The fluorescent labeling of alprenolol with DIBI was achieved in the presence of palladium acetate as a catalyst, and the labeled alprenolol was detected fluorometrically. In addition, it was found that the fluorescence of DIBI derivative increased and red shifted when compared with that of DIBI. Furthermore, the proposed method could be applied to determine the alprenolol concentration in rat plasma after administration of alprenolol without interferences from biological components. The detection limit (S/N=3) for alprenolol in rat plasma was 0.74 ng/mL (30 fmol on column)

    GABAA Receptor-Mediated Acceleration of Aging-Associated Memory Decline in APP/PS1 Mice and Its Pharmacological Treatment by Picrotoxin

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    Advanced age and mutations in the genes encoding amyloid precursor protein (APP) and presenilin (PS1) are two serious risk factors for Alzheimer's disease (AD). Finding common pathogenic changes originating from these risks may lead to a new therapeutic strategy. We observed a decline in memory performance and reduction in hippocampal long-term potentiation (LTP) in both mature adult (9–15 months) transgenic APP/PS1 mice and old (19–25 months) non-transgenic (nonTg) mice. By contrast, in the presence of bicuculline, a GABAA receptor antagonist, LTP in adult APP/PS1 mice and old nonTg mice was larger than that in adult nonTg mice. The increased LTP levels in bicuculline-treated slices suggested that GABAA receptor-mediated inhibition in adult APP/PS1 and old nonTg mice was upregulated. Assuming that enhanced inhibition of LTP mediates memory decline in APP/PS1 mice, we rescued memory deficits in adult APP/PS1 mice by treating them with another GABAA receptor antagonist, picrotoxin (PTX), at a non-epileptic dose for 10 days. Among the saline vehicle-treated groups, substantially higher levels of synaptic proteins such as GABAA receptor α1 subunit, PSD95, and NR2B were observed in APP/PS1 mice than in nonTg control mice. This difference was insignificant among PTX-treated groups, suggesting that memory decline in APP/PS1 mice may result from changes in synaptic protein levels through homeostatic mechanisms. Several independent studies reported previously in aged rodents both an increased level of GABAA receptor α1 subunit and improvement of cognitive functions by long term GABAA receptor antagonist treatment. Therefore, reduced LTP linked to enhanced GABAA receptor-mediated inhibition may be triggered by aging and may be accelerated by familial AD-linked gene products like Aβ and mutant PS1, leading to cognitive decline that is pharmacologically treatable at least at this stage of disease progression in mice

    Uresničevanje sistema javnih uslužbencev

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    The total synthesis of the resveratrol dimers (+/-)-ampelopsin B and (+/-)-E-viniferin is reported. Highlights of the approach include the use of cyclopropylmethyl groups to protect aromatic alcohols. This group allows an acid promoted three-step, one-pot deprotection-epimerization-cyclization of an advanced intermediate to give (+/-)-ampelopsin B. An important advantage with our strategy is the possibility of synthesizing analogs to these natural products to further study the chemistry and biology of resveratrol oligomers

    GSK-3β Is Required for Memory Reconsolidation in Adult Brain

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    Activation of GSK-3β is presumed to be involved in various neurodegenerative diseases, including Alzheimer's disease (AD), which is characterized by memory disturbances during early stages of the disease. The normal function of GSK-3β in adult brain is not well understood. Here, we analyzed the ability of heterozygote GSK-3β knockout (GSK+/−) mice to form memories. In the Morris water maze (MWM), learning and memory performance of GSK+/− mice was no different from that of wild-type (WT) mice for the first 3 days of training. With continued learning on subsequent days, however, retrograde amnesia was induced in GSK+/− mice, suggesting that GSK+/− mice might be impaired in their ability to form long-term memories. In contextual fear conditioning (CFC), context memory was normally consolidated in GSK+/− mice, but once the original memory was reactivated, they showed reduced freezing, suggesting that GSK+/− mice had impaired memory reconsolidation. Biochemical analysis showed that GSK-3β was activated after memory reactivation in WT mice. Intraperitoneal injection of a GSK-3 inhibitor before memory reactivation impaired memory reconsolidation in WT mice. These results suggest that memory reconsolidation requires activation of GSK-3β in the adult brain

    Bioinorganic Chemistry of Alzheimer’s Disease

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    Systematic Review of Potential Health Risks Posed by Pharmaceutical, Occupational and Consumer Exposures to Metallic and Nanoscale Aluminum, Aluminum Oxides, Aluminum Hydroxide and Its Soluble Salts

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    Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007). Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of “total Al”assumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold. The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al+ 3 to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)+ 2 and Al(H2O)6 + 3] that after complexation with O2•−, generate Al superoxides [Al(O2•)](H2O5)]+ 2. Semireduced AlO2• radicals deplete mitochondrial Fe and promote generation of H2O2, O2 • − and OH•. Thus, it is the Al+ 3-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates. Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer\u27s disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants. The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances
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