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result(s) for
"Johansson, J"
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The importance of reduced meat and dairy consumption for meeting stringent climate change targets
by
Johansson, Daniel J. A.
,
Wirsenius, Stefan
,
Hedenus, Fredrik
in
Agricultural land
,
agricultural soils
,
Agriculture
2014
For agriculture, there are three major options for mitigating greenhouse gas (GHG) emissions: 1) productivity improvements, particularly in the livestock sector; 2) dedicated technical mitigation measures; and 3) human dietary changes. The aim of the paper is to estimate long-term agricultural GHG emissions, under different mitigation scenarios, and to relate them to the emissions space compatible with the 2 °C temperature target. Our estimates include emissions up to 2070 from agricultural soils, manure management, enteric fermentation and paddy rice fields, and are based on IPCC Tier 2 methodology. We find that baseline agricultural CO
2
-equivalent emissions (using Global Warming Potentials with a 100 year time horizon) will be approximately 13 Gton CO
2
eq/year in 2070, compared to 7.1 Gton CO
2
eq/year 2000. However, if faster growth in livestock productivity is combined with dedicated technical mitigation measures, emissions may be kept to 7.7 Gton CO
2
eq/year in 2070. If structural changes in human diets are included, emissions may be reduced further, to 3–5 Gton CO
2
eq/year in 2070. The total annual emissions for meeting the 2 °C target with a chance above 50 % is in the order of 13 Gton CO
2
eq/year or less in 2070, for all sectors combined. We conclude that reduced ruminant meat and dairy consumption will be indispensable for reaching the 2 °C target with a high probability, unless unprecedented advances in technology take place.
Journal Article
Impacts of shared mobility on vehicle lifetimes and on the carbon footprint of electric vehicles
2022
Shared cars will likely have larger annual vehicle driving distances than individually owned cars. This may accelerate passenger car retirement. Here we develop a semi-empirical lifetime-driving intensity model using statistics on Swedish vehicle retirement. This semi-empirical model is integrated with a carbon footprint model, which considers future decarbonization pathways. In this work, we show that the carbon footprint depends on the cumulative driving distance, which depends on both driving intensity and calendar aging. Higher driving intensities generally result in lower carbon footprints due to increased cumulative driving distance over the vehicle’s lifetime. Shared cars could decrease the carbon footprint by about 41% in 2050, if one shared vehicle replaces ten individually owned vehicles. However, potential empty travel by autonomous shared vehicles—the additional distance traveled to pick up passengers—may cause carbon footprints to increase. Hence, vehicle durability and empty travel should be considered when designing low-carbon car sharing systems.
Shared cars are driven more, which could shorten their lifetimes. This could influence carbon dioxide emissions in car manufacturing. Sharing nonetheless reduces carbon footprints. Designing cars for durability can further enhance the benefits
Journal Article
Observation of the dynamical Casimir effect in a superconducting circuit
by
Johansson, G.
,
Wilson, C. M.
,
Simoen, M.
in
639/638/298/924
,
639/766/483/1139
,
Applied sciences
2011
Casimir on the move
Two mirrors held parallel to each other in a vacuum experience an attractive force, known as the Casimir effect, which combines aspects of quantum vacuum behaviour with relativity. The force arises when vacuum fluctuations — virtual particles flitting in and out of existence — reduce the radiation pressure between the plates and generate an inward force. The static effect has been well studied, but theory also predicts a dynamical Casimir effect arising from a mismatch of vacuum modes in time rather than space. This paper presents the first observation of this phenomenon in a superconducting circuit.
One of the most surprising predictions of modern quantum theory is that the vacuum of space is not empty. In fact, quantum theory predicts that it teems with virtual particles flitting in and out of existence. Although initially a curiosity, it was quickly realized that these vacuum fluctuations had measurable consequences—for instance, producing the Lamb shift
1
of atomic spectra and modifying the magnetic moment of the electron
2
. This type of renormalization due to vacuum fluctuations is now central to our understanding of nature. However, these effects provide indirect evidence for the existence of vacuum fluctuations. From early on, it was discussed whether it might be possible to more directly observe the virtual particles that compose the quantum vacuum. Forty years ago, it was suggested
3
that a mirror undergoing relativistic motion could convert virtual photons into directly observable real photons. The phenomenon, later termed the dynamical Casimir effect
4
,
5
, has not been demonstrated previously. Here we observe the dynamical Casimir effect in a superconducting circuit consisting of a coplanar transmission line with a tunable electrical length. The rate of change of the electrical length can be made very fast (a substantial fraction of the speed of light) by modulating the inductance of a superconducting quantum interference device at high frequencies (>10 gigahertz). In addition to observing the creation of real photons, we detect two-mode squeezing in the emitted radiation, which is a signature of the quantum character of the generation process.
Journal Article
Late-stage C–H functionalization offers new opportunities in drug discovery
by
Guillemard, Lucas
,
Kaplaneris, Nikolaos
,
Johansson, Magnus J.
in
631/154/309/2144
,
639/638/309/2144
,
Analytical Chemistry
2021
Over the past decade, the landscape of molecular synthesis has gained major impetus by the introduction of late-stage functionalization (LSF) methodologies. C–H functionalization approaches, particularly, set the stage for new retrosynthetic disconnections, while leading to improvements in resource economy. A variety of innovative techniques have been successfully applied to the C–H diversification of pharmaceuticals, and these key developments have enabled medicinal chemists to integrate LSF strategies in their drug discovery programmes. This Review highlights the significant advances achieved in the late-stage C–H functionalization of drugs and drug-like compounds, and showcases how the implementation of these modern strategies allows increased efficiency in the drug discovery process. Representative examples are examined and classified by mechanistic patterns involving directed or innate C–H functionalization, as well as emerging reaction manifolds, such as electrosynthesis and biocatalysis, among others. Structurally complex bioactive entities beyond small molecules are also covered, including diversification in the new modalities sphere. The challenges and limitations of current LSF methods are critically assessed, and avenues for future improvements of this rapidly expanding field are discussed. We, hereby, aim to provide a toolbox for chemists in academia as well as industrial practitioners, and introduce guiding principles for the application of LSF strategies to access new molecules of interest.
Late-stage C–H functionalization of complex molecules has emerged as a powerful tool in drug discovery. This Review classifies significant examples by reaction manifold and assesses the benefits and challenges of each approach. Avenues for future improvements of this fast-expanding field are proposed.
Journal Article
Autologous haematopoietic stem cell transplantation: a viable treatment option for CIDP
by
Strömberg, U
,
Andersen, O
,
Axelson, H W
in
Adolescent
,
Adrenal Cortex Hormones - administration & dosage
,
Adult
2014
Objective Only 70–80% of patients with chronic inflammatory demyelinating polyneuropathy (CIDP) respond satisfactorily to the established first-line immunomodulatory treatments. Autologous haematopoietic stem cell transplantation (AHSCT) has been performed as a last treatment resort in a few therapy-refractory cases with CIDP. We describe the results of AHSCT in 11 consecutive Swedish patients with therapy-refractory CIDP with a median follow-up time of 28 months. Method Case data were gathered retrospectively for AHSCT treatments in 11 patients with CIDP refractory to the first-line immunomodulatory treatments, intravenous high-dose immunoglobulin, corticosteroids and plasma exchange and to one or more second-line treatments used in 10 of the 11 patients. Results The median Inflammatory Neuropathy Cause and Treatment (INCAT) score within 1 month prior to AHSCT was 6 and the Rankin score 4. Total INCAT and Rankin scores improved significantly within 2–6 months after AHSCT and continued to do so at last follow-up. The motor action potential amplitudes (CMAP) improved already within 4 months (median) after AHSCT. Three of the 11 patients relapsed during the follow-up period, requiring retransplantation with AHSCT in one. Eight of the 11 patients maintained drug-free remission upon last follow-up. AHSCT was safe but on the short term associated with a risk of cytomegalovirus (CMV) and Epstein–Barr virus reactivation, CMV disease, haemorrhagic cystitis and pancreatitis. Conclusions Our results though hampered by the limited number of patients and the lack of a control group suggest AHSCT to be efficacious in therapy-refractory CIDP, with a manageable complication profile. Confirmation of these results is necessary through randomised controlled trials.
Journal Article
Late-stage meta-C–H alkylation of pharmaceuticals to modulate biological properties and expedite molecular optimisation in a single step
by
Guillemard, Lucas
,
Johansson, Magnus J.
,
Ackermann, Lutz
in
631/154/309/2144
,
639/638/309/2144
,
639/638/77/888
2024
Catalysed C–H activation has emerged as a transformative platform for molecular synthesis and provides new opportunities in drug discovery by late-stage functionalisation (LSF) of complex molecules. Notably, small aliphatic motifs have gained significant interest in medicinal chemistry for their beneficial properties and applications as
sp
3
-rich functional group bioisosteres. In this context, we disclose a versatile strategy with broad applicability for the ruthenium-catalysed late-stage
meta
-C(
sp
2
)–H alkylation of pharmaceuticals. This general protocol leverages numerous directing groups inherently part of bioactive scaffolds to selectivity install a variety of medicinally relevant bifunctional alkyl units within drug compounds. Our strategy enables the direct modification of unprotected lead structures to quickly generate an array of pharmaceutically useful analogues without resorting to de novo syntheses. Moreover, productive late-stage modulation of key biological characteristics of drug candidates upon remote C–H alkylation proves viable, highlighting the major benefits of our approach to offer in drug development programmes.
Installation of small aliphatic motifs within pharmaceuticals provides a medicinally relevant tool in drug discovery programmes. Here, the authors report a late-stage
meta
-C–H alkylation method facilitating the biological properties modulation of therapeutic agents.
Journal Article
Monolithic FAPbBr3 photoanode for photoelectrochemical water oxidation with low onset-potential and enhanced stability
2023
Despite considerable research efforts on photoelectrochemical water splitting over the past decades, practical application faces challenges by the absence of efficient, stable, and scalable photoelectrodes. Herein, we report a metal-halide perovskite-based photoanode for photoelectrochemical water oxidation. With a planar structure using mesoporous carbon as a hole-conducting layer, the precious metal-free FAPbBr
3
photovoltaic device achieves 9.2% solar-to-electrical power conversion efficiency and 1.4 V open-circuit voltage. The photovoltaic architecture successfully applies to build a monolithic photoanode with the FAPbBr
3
absorber, carbon/graphite conductive protection layers, and NiFe catalyst layers for water oxidation. The photoanode delivers ultralow onset potential below 0 V versus the reversible hydrogen electrode and high applied bias photon-to-current efficiency of 8.5%. Stable operation exceeding 100 h under solar illumination by applying ultraviolet-filter protection. The photothermal investigation verifies the performance boost in perovskite photoanode by photothermal effect. This study is significant in guiding the development of photovoltaic material-based photoelectrodes for solar fuel applications.
Lead halide perovskites excel in optical and electronic properties, drawing significant attention in solar fuel studies. Here, the authors report a stable FAPbBr
3
photoanode optimized for water oxidation to achieve a low onset potential and high applied bias photon-to-current efficiency.
Journal Article
Plot twist in the iron spin saga
2022
Over the past 25 years, the photo-induced spin-crossover behaviour of Fe(
II
) complexes has puzzled scientists. Now, a symmetry-breaking twisting mode has been observed during the relaxation of such a complex. Controlling its configuration using enantiopure counterions has also been shown to slow down the relaxation.
Journal Article
Late-stage synthesis of heterobifunctional molecules for PROTAC applications via ruthenium-catalysed C‒H amidation
by
Putra, Okky Dwichandra
,
Antermite, Daniele
,
Friis, Stig D.
in
631/154/309/2144
,
639/638/403/933
,
Biotin
2023
PROteolysis TArgeting Chimeras (PROTACs) are heterobifunctional molecules emerging as a powerful modality in drug discovery, with the potential to address outstanding medical challenges. However, the synthetic feasibility of PROTACs, and the empiric and complex nature of their structure-activity relationships continue to present formidable limitations. As such, modular and reliable approaches to streamline the synthesis of these derivatives are highly desirable. Here, we describe a robust ruthenium-catalysed late-stage C‒H amidation strategy, to access fully elaborated heterobifunctional compounds. Using readily available dioxazolone reagents, a broad range of inherently present functional groups can guide the C–H amidation on complex bioactive molecules. High selectivity and functional group tolerance enable the late-stage installation of linkers bearing orthogonal functional handles for downstream elaboration. Finally, the single-step synthesis of both CRBN and biotin conjugates is demonstrated, showcasing the potential of this methodology to provide efficient and sustainable access to advanced therapeutics and chemical biology tools.
PROTACs are uniquely powerful therapeutic agents, but their synthetic tractability significantly limit drug discovery programs. Here, the authors developed a single step synthesis of PROTAC conjugates via late stage ruthenium-catalysed C–H amidation.
Journal Article
Vibrational coherences in manganese single-molecule magnets after ultrafast photoexcitation
by
McNab Robbie
,
Eng, Julien
,
Penfold, Thomas J
in
Absorption spectroscopy
,
Anisotropy
,
Chemical bonds
2020
Magnetic recording using femtosecond laser pulses has recently been achieved in some dielectric media, showing potential for ultrafast data storage applications. Single-molecule magnets (SMMs) are metal complexes with two degenerate magnetic ground states and are promising for increasing storage density, but remain unexplored using ultrafast techniques. Here we have explored the dynamics occurring after photoexcitation of a trinuclear µ3-oxo-bridged Mn(iii)-based SMM, whose magnetic anisotropy is closely related to the Jahn–Teller distortion. Ultrafast transient absorption spectroscopy in solution reveals oscillations superimposed on the decay traces due to a vibrational wavepacket. Based on complementary measurements and calculations on the monomer Mn(acac)3, we conclude that the wavepacket motion in the trinuclear SMM is constrained along the Jahn–Teller axis due to the µ3-oxo and µ-oxime bridges. Our results provide new possibilities for optical control of the magnetization in SMMs on femtosecond timescales and open up new molecular-design challenges to control the wavepacket motion in the excited state of polynuclear transition-metal complexes.Controlling single-molecule magnets (SMMs) with ultrashort laser pulses could be key to future data storage devices, however, the photophysics of SMMs is complex. Now, using a monomer model system, it has been shown that optical excitation of Mn(iii)-SMMs leads to a modulation of the Jahn–Teller distortion, which is important for its magnetic anisotropy.
Journal Article