Ultrafast charge carrier separation in Potassium-intercalated endohedral metallofullerene Sc3_3N@C80_{80} thin films

Molecular materials have emerged as highly tunable materials for photovoltaic and light-harvesting applications. The most severe challenge of this class of materials is the trapping of charge carriers in bound electron-hole pairs, which severely limits the free charge carrier generation. Here, we demonstrate a significant modification of the exciton dynamics of thin films of endohedral metallofullerene complexes upon alkali metal intercalation. For the exemplary case of Sc$_3$N@C$_{80}$ thin films, we show that potassium intercalation results in an additional relaxation channel for the optically excited charge-transfer excitons that prevents the trapping of excitons in a long-lived Frenkel exciton-like state. Instead, K intercalation leads to an ultrafast exciton dissociation coinciding most likely with the generation of free charge carriers. In this way, we propose alkali metal doping of molecular films as a novel approach to enhance the light to-charge carrier conversion efficiency in photovoltaic materials

Recovery of scandium from acidic waste solutions by means of polymer inclusion membranes

Scandium is a raw material with properties that promise considerable potential for application in alloys to enable aviation fuel savings and as dopants for use in sustainable energy production using solid oxide fuel cells. Despite these attractive properties, scandium is rarely used due to its scarcity and unreliable supply. Therefore, new strategies for scandium recovery are of economic priority. In this study, polymer inclusion membranes (PIMs) consisting of PVDF-HFP, 2-NPOE and DEHPA, were optimised for selective scandium separation from real TiO2 production waste. With the optimised system, >60% of the scandium was recovered with high selectivity, resulting in scandium mole fraction at more than two orders of magnitude higher in the receiving phase than in the original waste. This suggests PIMs may be an effective way to recover scandium from bulk waste, thus easing the scarcity and insecurity that currently limit its bulk application

Ultrafast charge-transfer exciton dynamics in C60_{60} thin films

The high flexibility of organic molecules offers great potential for designing the optical properties of light-active materials for the next generation of optoelectronic and photonic applications. However, despite successful implementations of molecular materials in todays' display and photovoltaic technology, many fundamental aspects of the light-to-charge conversion have still to be uncovered. Here, we focus on the ultrafast dynamics of optically excited excitons in C$_{60}$ thin films depending on the molecular coverage and the light-polarization of the optical excitons. Using time- and momentum-resolved photoemission with fs-XUV radiation, we follow the depopulation dynamics in the excited states while simultaneously monitoring the signatures of the excitonic charge character in the molecular valence states. Optical excitation with visible light results in the instantaneous formation of charge-transfer (CT) excitons, which transform stepwise into energetically lower Frenkel-like excitons. While the number and energetic position of energy levels within this cascade process are independent of the molecular coverage and the light polarization of the optical excitation, we find quantitative differences in the depopulation times and the optical excitation efficiency. Our comprehensive study reveals the crucial role of CT excitons for the excited state dynamics of homo-molecular fullerene materials and thin films

Organic solvent free PbI₂ recycling from perovskite solar cells using hot water

Perovskite solar cells represent an emerging and highly promising renewable energy technology. However, the most efficient perovskite solar cells critically depend on the use of lead. This represents a possible environmental concern potentially limiting the technologiesâEurotm commercialization. Here, we demonstrate a facile recycling process for PbI2, the most common lead-based precursor in perovskite absorber material. The process uses only hot water to effectively extract lead from synthetic precursor mixes, plastic- and glass-based perovskites (92.6 âEuro" 10

Central memory phenotype drives success of checkpoint inhibition in combination with CAR T cells

The immunosuppressive microenvironment in solid tumors is thought to form a barrier to the entry and efficacy of cell-based therapies such as chimeric antigen receptor (CAR) T cells. Combining CAR T cell therapy with checkpoint inhibitors has been demonstrated to oppose immune escape mechanisms in solid tumors and augment antitumor efficacy. We evaluated PD-1/PD-L1 signaling capacity and the impact of an inhibitor of this checkpoint axis in an in vitro system for cancer cell challenge, the coculture of L1CAM-specific CAR T cells with neuroblastoma cell lines. Fluorescence-activated cell sorting-based analyses and luciferase reporter assays were used to assess PD-1/PD-L1 expression on CAR T and tumor cells as well as CAR T cell ability to kill neuroblastoma cells. Coculturing neuroblastoma cell lines with L1CAM-CAR T cells upregulated PD-L1 expression on neuroblastoma cells, confirming adaptive immune resistance. Exposure to neuroblastoma cells also upregulated the expression of the PD-1/PD-L1 axis in CAR T cells. The checkpoint inhibitor, nivolumab, enhanced L1CAM-CAR T cell-directed killing. However, nivolumab-enhanced L1CAM-CAR T cell killing did not strictly correlate with PD-L1 expression on neuroblastoma cells. In fact, checkpoint inhibitor success relied on strong PD-1/PD-L1 axis expression in the CAR T cells, which in turn depended on costimulatory domains within the CAR construct, and more importantly, on the subset of T cells selected for CAR T cell generation. Thus, T cell subset selection for CAR T cell generation and CAR T cell prescreening for PD-1/PD-L1 expression could help determine when combination therapy with checkpoint inhibitors could improve treatment efficacy

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

Wünsch M, Schröder DC, Fröhr T, et al. Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics. Beilstein Journal of Organic Chemistry. 2017;13:2428-2441.The amide moiety of peptides can be replaced for example by a triazole moiety, which is considered to be bioisosteric. Therefore, the carbonyl moiety of an amino acid has to be replaced by an alkyne in order to provide a precursor of such peptidomimetics. As most amino acids have a chiral center at C-alpha, such amide bond surrogates need a chiral moiety. Here the asymmetric synthesis of a set of 24 N-sulfinyl propargylamines is presented. The condensation of various aldehydes with Ellman's chiral sulfinamide provides chiral N-sulfinylimines, which were reacted with (trimethylsilyl) ethynyllithium to afford diastereomerically pure N-sulfinyl propargylamines. Diverse functional groups present in the propargylic position resemble the side chain present at the Ca of amino acids. Whereas propargylamines with (cyclo) alkyl substituents can be prepared in a direct manner, residues with polar functional groups require suitable protective groups. The presence of particular functional groups in the side chain in some cases leads to remarkable side reactions of the alkyne moiety. Thus, electron-withdrawing substituents in the C-alpha-position facilitate a base induced rearrangement to alpha, beta-unsaturated imines, while azide-substituted propargylamines form triazoles under surprisingly mild conditions. A panel of propargylamines bearing fluoro or chloro substituents, polar functional groups, or basic and acidic functional groups is accessible for the use as precursors of peptidomimetics

Long-term Outcomes in Patients With Multiple Myeloma

Registry data are important for monitoring the impact of new therapies on treatment algorithms and outcomes, and for guiding clinical decision making in multiple myeloma (MM). This observational study analyzed real-world data from patients in the Population-based HAematological Registry for Observational Studies who were treated for symptomatic MM from 2008 to 2013 in the Netherlands. The primary endpoint was overall survival (OS) from initiation of first-line treatment. Secondary endpoints included OS and progression-free survival per treatment line, treatment patterns, and treatment response. Between 2008 and 2013, 917, 583, 283, and 139 patients had initiated first, second, third, and fourth treatment lines, respectively. Thalidomide-based regimens were the most frequently used first-line treatment (66%); bortezomib- and lenalidomide-based regimens were most often used in the second line (41% and 27%, respectively). The median OS (95% confidence interval) ranged from 37.5 months (34.8–41.8 months) in the first line to 9.2 months (6.2–12.3 months) in the fourth line. Univariate analyses showed that survival benefits were most apparent in younger patients (65 vs >65 years). These analyses provide important real-world information on treatment patterns and outcomes in patients with MM

Element recovery from acidic waste streams

The world is facing a rising demand for resources, as a result of both the expanding human population and increasing affluence across the globe. Consequently, some nations have started to declare specific resources as critical due to their economic importance, while being at risk of supply shortage. One such critical raw material is scandium (Sc), a light-weight rare earth metal. Although not widely used yet, its unique physicochemical properties offer advantages for the transport and energy sectors that could lead to disruptive changes. For instance, Sc could foster large scale additive manufacturing of ultra-light car bodies for aircraft or other vehicles. Furthermore, it is crucial for commercial solid oxide fuel cells, which represent one of the best available technologies for hydrogen-based electricity supply. Unfortunately, the production of Sc is limited by the availability of concentrated ores. Hence, although an estimated 6 Mt of Sc could be available, the annual production is only about ~20 t. Notably, Sc was found in comparably high concentrations in bulk industrial wastes, such as bauxite residues and white pigment acid waste from production of aluminium and titanium oxides respectively. Overall, this makes Sc a prime example for the development of novel hydrometallurgical strategies that allow for sustainable element recovery. Membrane processes are an attractive option for this purpose, as they can provide ion-selective separation that complements established procedures, while generally having a low material footprint. In this thesis, two advanced membrane procedures were selected to investigate their potential for Sc recovery in a realworld scenario. Therefore, based on European $\textrm{TiO}_2$ acid waste, acid resistant nanofiltration and liquid membrane extraction using polymer inclusion membranes were extensively researched. The conducted studies included the manufacturing and optimisation of tailor-made nanofiltration and polymer inclusion membranes, culminating in the development of a process cascade for Sc recovery, that was eventually piloted on cubic metre scale. The results presented here may contribute to the establishment of future Sc supply from secondary streams. However, they are also expected to have broader implications beyond Sc recovery, potentially extending to other critical raw materials. Thus, this work advances the role of membranes in hydrometallurgy and may ultimately facilitate strategies for a more sustainable supply of resources