Herein, we disclose a strategy for the activation of N‐(acyloxy)phthalimides towards photoinduced electron transfer through hydrogen bonding. This activation mode enables efficient access to ...C(sp3)‐centered radicals upon decarboxylation from bench‐stable and readily available substrates. Moreover, we demonstrate that the formed alkyl radicals can be successfully employed in a novel redox‐neutral method for constructing sp3−sp3 bonds across styrene moieties that gives straightforward access to complex alcohol and ether scaffolds.
OH, I see: An efficient strategy to activate N‐(acyloxy)phthalimides towards direct photoinduced electron transfer with photoexcited catalysts was developed. This strategy enables efficient visible‐light‐mediated formation of alkyl radicals that can be used to achieve the challenging oxyalkylation of styrenes under mild redox‐neutral conditions.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Euglena gracilis accumulates high levels of nickel.•Extracellular magnesium and copper limit the nickel uptake.•Histidine synthesis is activated by nickel.•Thiol-molecule pools are depressed by ...nickel.•Nickel is more noxious for energetic pathways of E. gracilis than cadmium.
Nickel accumulation and nickel effects on cellular growth, respiration, photosynthesis, ascorbate peroxidase (APX) activity, and levels of thiols, histidine and phosphate-molecules were determined in Euglena gracilis. Cells incubated with 0.5–1mM NiCl2 showed impairment of O2 consumption, photosynthesis, Chl a+b content and APX activity whereas cellular integrity and viability were unaltered. Nickel accumulation was depressed by Mg2+ and Cu2+, while Ca2+, Co2+, Mn2+ and Zn2+ were innocuous. The growth half-inhibitory concentrations for Ni2+ in the culture medium supplemented with 2 or 0.2mM Mg2+ were 0.43 or 0.03mM Ni2+, respectively. Maximal nickel accumulation (1362mg nickel/Kg DW) was achieved in cells exposed to 1mM Ni2+ for 24h in the absence of Mg2+ and Cu2+; accumulated nickel was partially released after 72h. GSH polymers content increased or remained unchanged in cells exposed to 0.05–1mM Ni2+; however, GSH, cysteine, γ-glutamylcysteine, and phosphate-molecules all decreased after 72h. Histidine content increased in cells stressed with 0.05 and 0.5mM Ni2+ for 24h but not at longer times. It was concluded that E. gracilis can accumulate high nickel levels depending on the external Mg2+ and Cu2+ concentrations, in a process in which thiols, histidine and phosphate-molecules have a moderate contribution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Highly selective tandem nucleophilic addition/cross‐coupling reactions of alkynes have been developed using visible‐light‐promoted dual gold/photoredox catalysis. The simultaneous oxidation of AuI ...and coordination of the coupling partner by photo‐generated aryl radicals, and the use of catalytically inactive gold precatalysts allows for high levels of selectivity for the cross‐coupled products without competing hydrofunctionalization or homocoupling. As demonstrated in representative arylative Meyer–Schuster and hydration reactions, this work expands the scope of dual gold/photoredox catalysis to the largest class of substrates for gold catalysts and benefits from the mild and environmentally attractive nature of visible‐light activation.
United we stand! Tandem nucleophilic addition/cross‐coupling reactions have been developed with challenging alkynes using a visible‐light‐promoted dual gold/photoredox catalytic system (see scheme). High levels of selectivity for the cross‐coupled products were obtained without competition from the homocoupling or conventional hydrofunctionalization.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Herein, we report a new visible‐light‐promoted strategy to access radical trifluoromethylthiolation reactions by combining halide and photoredox catalysis. This approach allows for the synthesis of ...vinyl–SCF3 compounds of relevance in pharmaceutical chemistry directly from alkenes under mild conditions with irradiation from household light sources. Furthermore, alkyl–SCF3‐containing cyclic ketone and oxindole derivatives can be accessed by radical‐polar crossover semi‐pinacol and cyclization processes. Inexpensive halide salts play a crucial role in activating the trifluoromethylthiolating reagent towards photoredox catalysis and aid the formation of the SCF3 radical.
Ha(light)! A visible‐light‐promoted strategy to access SCF3 radicals under mild conditions has been developed by combining halide and photoredox catalysis (see scheme). This dual catalytic system enables the synthesis of pharmaceutically relevant vinyl–SCF3 compounds directly from styrenes. Furthermore, alkyl–SCF3‐containing cyclic ketone and oxindole derivatives can be accessed by a radical‐polar crossover semi‐pinacol rearrangement and cyclization, respectively. Halide salts play a crucial role in aiding the photo‐mediated formation of SCF3 radicals.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The development of new hydrogen‐atom transfer (HAT) strategies within the framework of photoredox catalysis is highly appealing for its power to activate a desired C−H bond in the substrate leading ...to its selective functionalization. Reported here is the first photoredox‐mediated hydrogen‐atom transfer method for the efficient synthesis of ynones, ynamides, and ynoates with high regio‐ and chemoselectivity by direct functionalization of Csp2
(O)−H bonds. The broad synthetic application of this method has been demonstrated by the selective functionalization of C(O)−H bonds within complex molecular scaffolds.
Tip your HAT: A photoredox‐catalyzed hydrogen‐atom transfer (HAT) method has been developed for the successful generation of carbonyl radicals from aldehydes and analogous compounds with an XC(O)−H (X=N, O) group. The successful trapping of the carbonyl radicals with ethynylbenziodoxolone (EBX) reagents provides a route for the synthesis of ynones, ynamides, and ynoates from readily available starting materials.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Eugenic ideas in Mexico were popularised after the Mexican Revolution (1910–1920) as a way of ‘modernising’ and ‘civilising’ the nation. As a result, eugenic ideas were able to linger and be ...maintained through different departments, institutions, and individuals from all disciplines. After eugenics was considered a pseudoscience, its practices and ideas continued through population control measures that targeted indigenous populations for sterilisation, a trend that still prevails. The purpose of this article is to explore the legacies of eugenics in current sterilizations procedures mostly targeted at indigenous communities in Mexico. I offer the term ‘slippery eugenics’ to account for the legacies of eugenics in Mexico which, in this specific case, resurface in the systematic forced and coerced sterilisation procedures targeted at indigenous communities.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK, VSZLJ
Herein, we report a novel strategy for the activation of DMSO to act as a versatile alkylating agent in heteroarene C−H functionalization. This direct, simple, and mild switch between ...methylation/trideuteromethylation and methylthiomethylation of heteroarenes was achieved under reagent‐controlled photoredox catalysis conditions. The proposed mechanism is supported by both experimental and computational studies.
Mild alkylation: A direct, simple, and mild methylation, trideuteromethylation, and methylthiomethylation of heteroarenes using DMSO as an alkylating agent is reported. This novel strategy was achieved under reagent‐controlled photoredox catalysis conditions. The proposed mechanism is supported by both experimental and theoretical studies.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
AbstractPressure management (PM) is commonly used in water distribution systems (WDSs). In the last decade, a strategic objective in the field has been the development of new scientific and technical ...methods for its implementation. However, due to a lack of systematic analysis of the results obtained in practical cases, progress has not always been reflected in practical actions. To address this problem, this paper provides a comprehensive analysis of the most innovative issues related to PM. The methodology proposed is based on a case-study comparison of qualitative concepts that involves published work from 140 sources. The results include a qualitative analysis covering four aspects: (1) the objectives yielded by PM; (2) types of regulation, including advanced control systems through electronic controllers; (3) new methods for designing districts; and (4) development of optimization models associated with PM. The evolution of the aforementioned four aspects is examined and discussed. Conclusions regarding the current status of each factor are drawn and proposals for future research outlined.
The high plasma temperatures expected at reactor conditions in magnetic confinement fusion toroidal devices suggest that near-marginal operation could be a reality in future devices and reactors. By ...near-marginal it is meant that the plasma profiles might wander around the local critical thresholds for the onset of instabilities. Self-organized criticality (SOC) was suggested in the mid 1990s as a more proper paradigm to describe the dynamics of tokamak plasma transport in near-marginal conditions. It advocated that, near marginality, the evolution of mean profiles and fluctuations should be considered simultaneously, in contrast to the more common view of a large separation of scales existing between them. Otherwise, intrinsic features of near-marginal transport would be missed, that are of importance to understand the properties of energy confinement. In the intervening 20 years, the relevance of the idea of SOC for near-marginal transport in fusion plasmas has transitioned from an initial excessive hype to the much more realistic standing of today, which we will attempt to examine critically in this review paper. First, the main theoretical ideas behind SOC will be described. Secondly, how they might relate to the dynamics of near-marginal transport in real magnetically confined plasmas will be discussed. Next, we will review what has been learnt about SOC from various numerical studies and what it has meant for the way in which we do numerical simulation of fusion plasmas today. Then, we will discuss the experimental evidence available from the several experiments that have looked for SOC dynamics in fusion plasmas. Finally, we will conclude by identifying the various problems that still remain open to investigation in this area. Special attention will be given to the discussion of frequent misconceptions and ongoing controversies. The review also contains a description of ongoing efforts that seek effective transport models better suited than traditional equations to capture SOC dynamics. Most of these models, based on the use of fractional transport equations and related concepts, could prove useful both in reactor operation and experiment control and design.
Background and Objectives
Vitamin D binding protein (DBP) is biosynthesised in the liver and is predominantly expressed in serum. Its primary role centres on facilitating the systemic transportation ...of vitamin D and its metabolites, notably 25‐hydroxyvitamin D, to specific target tissues where vitamin D exerts its biological functions. Due to the paucity of studies, it is unclear whether there is an association between DBP and periodontal status and thus its potential use as a diagnostic biomarker. Therefore, the aim of the systematic review is to investigate the association between DBP in periodontal disease.
Methods
Two independent reviewers (YD and RG) performed a systematic literature search of English publications using several databases including MEDLINE (OVID interface, 1946 onwards), EMBASE (OVID interface, 1974 onwards), and Global Health (OVID interface, 1973 onwards). This search strategy enabled the identification of relevant publications and the development of a comprehensive library of studies. Studies were included based on previously agreed eligibility criteria. Of the eight studies included as part of this systematic review, seven were case–control studies and one was a cross‐sectional study. The quality assessment was based on the Newcastle–Ottawa Scale (NOS) for case–control studies and the modified NOS for the cross‐sectional study.
Results
The NOS quality assessment was ‘favorable’ for 6 included case control studies; and ‘fair’ for one study. The modified NOS quality assessment for the single cross‐sectional study demonstrated a medium risk of bias. The results of the majority of the included studies indicated a statistically significant higher concentration of DBP levels in individuals with periodontitis in comparison to those who were periodontally healthy. This trend held true irrespective of the sampling method employed for the assessment of DBP concentration.
Conclusion
The results summarised in this systematic review indicate a positive association between DBP and periodontitis. Nonetheless, there is a need for longitudinal, prospective trials, to confirm the use of DBP as a potential biomarker for the diagnosis of periodontitis.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
