Shuttle arylation by Rh(I) catalyzed reversible carbon–carbon bond activation of unstrained alcohols

The advent of transfer hydrogenation and borrowing hydrogen reactions paved the way to manipulate simple alcohols in previously unthinkable manners and circumvented the need for hydrogen gas. Analogously, transfer hydrocarbylation could greatly increase the versatility of tertiary alcohols. However, this reaction remains unexplored because of the challenges associated with the catalytic cleavage of unactivated C–C bonds. Herein, we report a rhodium(I)-catalyzed shuttle arylation cleaving the C(sp2)–C(sp3) bond in unstrained triaryl alcohols via a redox-neutral β-carbon elimination mechanism. A selective transfer hydrocarbylation of substituted (hetero)aryl groups from tertiary alcohols to ketones was realized, employing benign alcohols as latent C-nucleophiles. All preliminary mechanistic experiments support a reversible β-carbon elimination/migratory insertion mechanism. In a broader context, this novel reactivity offers a new platform for the manipulation of tertiary alcohols in catalysis.ISSN:2451-9294ISSN:2451-930

Shuttle Arylation by Rh(I) Catalyzed Reversible Carbon–Carbon Bond Activation of Unstrained Alcohols

The advent of transfer hydrogenation and borrowing hydrogen reactions paved the way to manipulate simple alcohols in previously unthinkable manners and circumvent the need for hydrogen gas. Analogously, transfer hydrocarbylation could greatly increase the versatility of tertiary alcohols. However, this reaction remains unexplored because of the challenges associated with the catalytic cleavage of unactivated C–C bonds. Herein, we report a rhodium(I)-catalyzed shuttle arylation cleaving the C(sp2)–C(sp3) bond in unstrained triaryl alcohols via a redox-neutral β-carbon elimination mechanism. A selective transfer hydrocarbylation of substituted (hetero)aryl groups from tertiary alcohols to ketones was realized, employing benign alcohols as latent C-nucleophiles. All preliminary mechanistic experiments support a reversible β-carbon elimination/migratory insertion mechanism. In a broader context, this novel reactivity offers a new platform for the manipulation of tertiary alcohols in catalysis

Toxic effects of lipid-mediated gene transfer in ventral mesencephalic explant cultures

Adverse effects of cDNA and oligonucleotide delivery methods have not yet been systematically analyzed. We introduce a protocol to monitor toxic effects of two non-viral lipid-based gene delivery protocols using CNS primary tissue. Cell membrane damage was monitored by quantifying cellular uptake of propidium iodide and release of cytosolic lactate dehydrogenase to the culture medium. Using a liposomal transfection reagent, cell membrane damage was already seen 24 hr after transfection. Nestin-positive target cells, which were used as morphological correlate, were severely diminished in some areas of the cultures after liposomal transfection. In contrast, the non-liposomal transfection reagent revealed no signs of toxicity. This approach provides easily accessible information of transfection-associated toxicity and appears suitable for prescreening of transfection reagents

Unge muslimske stemmer

De som kommer til orde i denne boka er den moderate majoriteten av unge norske muslimer. De reflekterer om deres personlige tro, religiøse praksis, gruppetilhørigheter og særlig om synet de har på ekstreme bevegelser. Slik får vi en rikere forståelse av den motstanden mot jihadisme som er vanlig blant norske muslimer - omfanget, styrken, grunnene og engasjementet. Boka tar samtidig for seg at det er store forskjeller blant «vanlige» muslimer når det gjelder fortolkninger av islam, og at det er kamp mellom moderate og mer ekstreme strømninger om definisjonene av grunnleggende begreper og fortellinger. En rød tråd i boka er at det ikke nødvendigvis er politiet, kommunene eller andre offentlige instanser som er frontlinjen for bekjempelse av ekstremisme. Voldelig jihadisme bekjempes daglig i muslimske miljøer, og en viktig del av dette er kampen mellom forskjellige fortolkninger av islam

Ageing response of an Al-Mg-Mn-Sc-Zr alloy processed by laser metal deposition in thin-wall structures

The use of aluminium alloys containing Sc and Zr in additive manufacturing (AM) provides new solutions for lightweight design. Representative thin-wall structured parts were additively fabricated with a commercially available Al-4.55Mg-0.51Mn-0.65Sc-0.30Zr alloy in Laser Metal Deposition (LMD) process. A bi-directional and a uni-directional scan strategy were applied and laser power from 500 W to 600 W was used. Nanohardness tests were conducted on specimens aged at 300 °C for up to 19 h to observe the ageing responses. Fine-grained microstructures with few micro-sized precipitates containing Sc- and Zr were found in the last track of every specimen. The area formed by the track-overlapping was the opposite, but an apparent hardening was observed only after the ageing. AM-processes with local remelting are facing the challenge to exert the potential strengthening effect of aluminium alloys containing Sc. The mushy state must be suppressed to prevent the waste of the expensive rare elements

Laser Directed Energy Deposition of an AlMgScZr-Alloy in High-Speed Process Regimes

Aluminum-magnesium-scandium-zirconium (AlMgScZr) alloys need to be rapidly cooled from the liquid state to obtain a high degree of solute supersaturation that helps to exploit the precipitation hardening potential of the material. While AlMgScZr alloys have been successfully used in laser powder bed fusion (LPBF) processes, there has been little research in the field of laser directed energy deposition (DED) of the material. The limited previous studies have shown that the performance of AlMgScZr parts fabricated with DED only reached about 60% of that of the parts fabricated with LPBF. In view of breaking through the limitation associated with the process conditions of conventional DED, this work demonstrates the DED of AlMgScZr alloys in high-speed process regimes and elucidates the mechanism of enhancing the hardness and tensile strength of AlMgScZr alloys by increasing the cooling rate by one to two orders of magnitudes, as well as reducing the track overlapping and the porosity of the specimens during the process. A maximum average hardness of nearly 150 HV0.1 and a max. tensile strength of 407 MPa are obtained by using an energy per unit length of 5400 J/m and a powder feed rate per unit length of 0.25 g/m

Parathyroid hormone analogues in the treatment of osteoporosis

Osteoporosis is characterized by the occurrence of fragility fractures. Over the past years, various treatment options have become available, mostly antiresorptive agents such as bisphosphonates. However, antiresorptive therapy cannot restore bone mass and structure that has been lost due to increased remodeling. In this case, recombinant human parathyroid hormone (PTH) analogues-the full-length PTH(1-84) or the shortened molecule PTH(1-34), which is also known as teriparatide-present the possibility of increasing the formation of new bone substance by virtue of their anabolic effects. The bone formation induced by PTH analogues not only increases BMD or bone mass but also improves the microarchitecture of the skeleton, thereby leading to improved strength of bone and increased mechanical resistance. Controlled trials have shown that both analogues significantly reduce the incidence of vertebral fractures, and PTH(1-34) also reduces the risk of nonvertebral fractures. The need for daily self-injection and the higher cost compared with other forms of treatment limit the widespread use of PTH analogues. Nevertheless, treatment with PTH analogues should be considered in postmenopausal women and men with severe osteoporosis, as well as in patients on established glucocorticoid treatment with a high fracture risk. Concurrent therapy with antiresorptive agents should be avoided, but sequential therapy with these agents might consolidate the beneficial effects on the skeleton