396 research outputs found

    A short sequence for the iterative synthesis of fused polyethers

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    A simple and efficient four‐step sequence for the synthesis of fused polyether arrays has been developed. Cyclic ethers are installed by sequential alkynyl ether formation, carbocupration, ring‐closing metathesis and hydroboration with acidic workup. Crucially, the alkene required for the subsequent ring formation by ring‐closing metathesis is present in the substrate but is masked in the form of a vinylic silane, which prevents competitive metathesis of the side chain. Generation of the reactive alkene from the unreactive vinylic silane is accomplished by hydroboration and subsequent acid‐mediated Peterson elimination of the intermediate hydroxysilane

    Intra-arterial induction high-dose chemotherapy with cisplatin for oral and oropharyngeal cancer: long-term results

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    Intra-arterial (IA) chemotherapy for curative treatment of head and neck cancer experienced a revival in the last decade. Mainly, it was used in concurrent combination with radiation in organ-preserving settings. The modern method of transfemoral approach for catheterisation, superselective perfusion of the tumour-feeding vessel, and high-dose (150 mg m−2) administration of cisplatin with parallel systemic neutralisation with sodium thiosulphate (9 g m−2) made preoperative usage feasible. The present paper presents the results of a pilot study on a population of 52 patients with resectable stage 1–4 carcinomas of the oral cavity and the oropharynx, who were treated with one cycle of preoperative IA chemotherapy executed as mentioned above and radical surgery. There have been no interventional complications of IA chemotherapy, and acute side effects have been low. One tracheotomy had to be carried out due to swelling. The overall clinical local response has been 69%. There was no interference with surgery, which was carried out 3–4 weeks later. Pathological complete remission was assessed in 25%. The mean observation time was 3 years. A 3-year overall and disease-free survival was 82 and 69%, respectively, and at 5 years 77 and 59%, respectively. Survival results were compared to a treatment-dependent prognosis index for the same population. As a conclusion, it can be stated that IA high-dose chemotherapy with cisplatin and systemic neutralisation in a neoadjuvant setting should be considered a feasible, safe, and effective treatment modality for resectable oral and oropharyngeal cancer. The low toxicity of this local chemotherapy recommends usage especially in stage 1–2 patients. The potential of survival benefit as indicated by the comparison to the prognosis index should be controlled in a randomised study

    Rapid, metal-free and aqueous synthesis of imidazo[1,2-a]pyridine under ambient conditions

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    A novel, rapid and efficient route to imidazo[1,2-a]pyridines under ambient, aqueous and metal-free conditions is reported. The NaOH-promoted cycloisomerisations of N-propargylpyridiniums give quantitative yield in a few minutes (10 g scale). A comparison of common green metrics to current routes showed clear improvements, with at least a one order of magnitude increase in space-time-yield

    Presenilin Is the Molecular Target of Acidic γ-Secretase Modulators in Living Cells

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    The intramembrane-cleaving protease γ-secretase catalyzes the last step in the generation of toxic amyloid-β (Aβ) peptides and is a principal therapeutic target in Alzheimer's disease. Both preclinical and clinical studies have demonstrated that inhibition of γ-secretase is associated with prohibitive side effects due to suppression of Notch processing and signaling. Potentially safer are γ-secretase modulators (GSMs), which are small molecules that selectively lower generation of the highly amyloidogenic Aβ42 peptides but spare Notch processing. GSMs with nanomolar potency and favorable pharmacological properties have been described, but the molecular mechanism of GSMs remains uncertain and both the substrate amyloid precursor protein (APP) and subunits of the γ-secretase complex have been proposed as the molecular target of GSMs. We have generated a potent photo-probe based on an acidic GSM that lowers Aβ42 generation with an IC50 of 290 nM in cellular assays. By combining in vivo photo-crosslinking with affinity purification, we demonstrated that this probe binds the N-terminal fragment of presenilin (PSEN), the catalytic subunit of the γ-secretase complex, in living cells. Labeling was not observed for APP or any of the other γ-secretase subunits. Binding was readily competed by structurally divergent acidic and non-acidic GSMs suggesting a shared mode of action. These findings indicate that potent acidic GSMs target presenilin to modulate the enzymatic activity of the γ-secretase complex

    Neural Correlates of Face and Object Perception in an Awake Chimpanzee (Pan Troglodytes) Examined by Scalp-Surface Event-Related Potentials

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    BACKGROUND: The neural system of our closest living relative, the chimpanzee, is a topic of increasing research interest. However, electrophysiological examinations of neural activity during visual processing in awake chimpanzees are currently lacking. METHODOLOGY/PRINCIPAL FINDINGS: In the present report, skin-surface event-related brain potentials (ERPs) were measured while a fully awake chimpanzee observed photographs of faces and objects in two experiments. In Experiment 1, human faces and stimuli composed of scrambled face images were displayed. In Experiment 2, three types of pictures (faces, flowers, and cars) were presented. The waveforms evoked by face stimuli were distinguished from other stimulus types, as reflected by an enhanced early positivity appearing before 200 ms post stimulus, and an enhanced late negativity after 200 ms, around posterior and occipito-temporal sites. Face-sensitive activity was clearly observed in both experiments. However, in contrast to the robustly observed face-evoked N170 component in humans, we found that faces did not elicit a peak in the latency range of 150-200 ms in either experiment. CONCLUSIONS/SIGNIFICANCE: Although this pilot study examined a single subject and requires further examination, the observed scalp voltage patterns suggest that selective processing of faces in the chimpanzee brain can be detected by recording surface ERPs. In addition, this non-invasive method for examining an awake chimpanzee can be used to extend our knowledge of the characteristics of visual cognition in other primate species

    Social times, reproduction and social inequality at work : contrasts and comparative perspectives between countries

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    Production of INCASI Project H2020-MSCA-RISE-2015 GA 691004If the focus is placed specifically on the problem of work and family, the daily life of people and their use of time are a main problem. This time is expressed in both freely available time, which is related to activities, and time of the productive and reproductive sphere. This chapter considers work in a broad sense and takes into account the sexual division of labour. Specifically, this chapter will explore transformations in time use and social inequality in unpaid work. For this purpose, a comparative analysis of time-use surveys will be used, analysing the time spent, and the time dedicated to household chores in Chile, Argentina, Uruguay and Spain. From an analytical viewpoint, the analysis will place social reproduction at the centre of the socio-economic system, showing that the economic crisis has affected women and men differently, and that in both Europe and Latin America the family pattern is being replaced by a dominant family model of a male provider and a double presence of women. The large-scale incorporation of women into the labour market has emphasised the role that women assume in the domestic sphere perpetuating gender segregation in employment and in domestic and care work

    Notch signaling as a therapeutic target for breast cancer treatment?

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    Aberrant Notch signaling can induce mammary gland carcinoma in transgenic mice, and high expressions of Notch receptors and ligands have been linked to poor clinical outcomes in human patients with breast cancer. This suggests that inhibition of Notch signaling may be beneficial for breast cancer treatment. In this review, we critically evaluate the evidence that supports or challenges the hypothesis that inhibition of Notch signaling would be advantageous in breast cancer management. We find that there are many remaining uncertainties that must be addressed experimentally if we are to exploit inhibition of Notch signaling as a treatment approach in breast cancer. Nonetheless, Notch inhibition, in combination with other therapies, is a promising avenue for future management of breast cancer. Furthermore, since aberrant Notch4 activity can induce mammary gland carcinoma in the absence of RBPjκ, a better understanding of the components of RBPjκ-independent oncogenic Notch signaling pathways and their contribution to Notch-induced tumorigenesis would facilitate the deployment of Notch inhibition strategies for effective treatment of breast cancer

    Gender-Specific Effects of Unemployment on Family Formation: A Cross-National Perspective

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    This paper investigates the impact of unemployment on the propensity to start a family. Unemployment is accompanied by bad occupational prospects and impending economic deprivation, placing the well-being of a future family at risk. I analyze unemployment at the intersection of state-dependence and the reduced opportunity costs of parenthood, distinguishing between men and women across a set of welfare states. Using micro-data from the European Community Household Panel (ECHP), I apply event history methods to analyze longitudinal samples of first-birth transitions in France, Finland, Germany, and the UK (1994-2001). The results highlight spurious negative effects of unemployment on family formation among men, which can be attributed to the lack of breadwinner capabilities in the inability to financially support a family. Women, in contrast, show positive effects of unemployment on the propensity to have a first child in all countries except France. These effects prevail even after ontrolling for labour market and income-related factors. The findings are pronounced in Germany and the UK where work-family conflicts are the cause of high opportunity costs of motherhood, and the gender-specific division of labour is still highly traditional. Particularly among women with a moderate and low level of education, unemployment clearly increases the likelihood to have a first child

    Estimating the Impact of the Recent Economic Crisis on Work Time in Turkey

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    This paper provides estimates of the impact of the recent economic crisis on paid and unpaid work time in Turkey. The data used in this study come from the first and only time-use survey available at the national level. Infrequency of collection of time-use data in Turkey does not allow us to make a direct comparison of pre-versus postcrisis time-use patterns. We introduce a tractable way for estimating these possible effects by measuring the impact of an increase in unemployment risk on time-use patterns of women and men living in couple households. The method developed here can be applied to other developing-country cases where there is a lack of longitudinal data availability. Our findings support the argument that economic crises reinforce the preexisting gender inequalities in work time
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