Designer enzymes for industrial applications

Arzeda is harnessing the power of computational and synthetic biology to design new enzymes and chemical products. In partnership with Fortune 500 companies and industrial leaders, we have developed a portfolio of enzymes and specialty chemicals for polymers, advanced materials and health and nutrition products. Arzeda’s proprietary platform and validation process rapidly and reliable engineers new enzyme - key to enabling customized bio-processes. We will illustrate how Arzeda’s computational design technology is applied to engineer enzymes features for applications in bio-based chemical production and agricultural traits

Differential appearance of dynamin in constitutive and regulated exo-endocytosis: a single-cell multiplex RT-PCR study

Neurons in the central nervous system establish, via their axons and dendrites, an extended network that allows synaptic transmission. During developmental maturation and process outgrowth, membrane turnover is necessary for the enlargement and subsequent growth of axons and dendrites from the perikarya to the target cell (constitutive exocytosis/endocytosis). After targeting and synapse formation, small synaptic vesicles are needed for the quantal release of neurotransmitters from the presynaptic terminal with subsequent recycling by regulated exocytosis/endocytosis. An investigation of the onset of the appearance of mRNA and protein in dissociated cultures of neurons from mouse hippocampus or from chick retina has shown an early abundance of proteins involved in exocytosis, such as syntaxin 1, SNAP-25, and synaptotagmin 1, whereas dynamin 1, a protein necessary for clathrin-mediated endocytosis, can be detected only after neurons have established contacts with neighboring cells. The results reveal that constitutive membrane incorporation and regulated synaptic transmitter release is mediated by the same neuronal proteins. Moreover, the data exclude that dynamin 1 takes part in constitutive recycling before synapse formation, but dynamin 2 is present at this stage. Thus, dynamin 2 may be the constitutive counterpart of dynamin 1 in growing neurons. Synapse establishment is linked to an upregulation of dynamin 1 and thereby represents the beginning of the regulated recycling of membranes back into the presynaptic termina

Large magnetoresistance effect due to spin-injection into a non-magnetic semiconductor

A novel magnetoresistance effect, due to the injection of a spin-polarized electron current from a dilute magnetic into a non-magnetic semiconductor, is presented. The effect results from the suppression of a spin channel in the non-magnetic semiconductor and can theoretically yield a positive magnetoresistance of 100%, when the spin flip length in the non-magnetic semiconductor is sufficiently large. Experimentally, our devices exhibit up to 25% magnetoresistance.Comment: 3 figures, submitted for publicatio

Detection of electrical spin injection by light-emitting diodes in top- and side-emission configuration

Detection of the degree of circular polarization of the electroluminescence of a light-emitting diode fitted with a spin injecting contact (a spin-LED) allows for a direct determination of the spin polarization of the injected carriers. Here, we compare the detection efficiency of (Al,Ga)As spin-LEDs fitted with a (Zn,Be,Mn)Se spin injector in top- and side-emission configuration. In contrast with top emission, we cannot detect the electrical spin injection in side emission from analysing the degree of circular polarization of the electroluminescence. To reduce resonant optical pumping of quantum-well excitons in the side emission, we have analysed structures with mesa sizes as small as 1 micron.Comment: 15 pages with 3 figure

Expression of SV2 in the developing chick cerebellum: comparison with Calbindin and AMPA glutamate receptors 2/3

The well-organized cerebellum is an ideal model to investigate the developmental appearance and localization of pre- and postsynaptic structures. One of the synaptic proteins abundant in the central nervous system and localized in presynaptic vesicle membranes is the synaptic vesicle protein 2 (SV2). SV2 was shown to be involved in priming and modulating synaptic vesicles and having an effect in epileptic diseases. So far there are no data available describing the developmental localization of this protein in the cerebellum. We followed the expression pattern of SV2 and compared it with the expression of the neuronal calcium-binding protein Calbindin and the AMPA glutamate receptor subunits 2/3 (GluR 2/3), both shown to be early expressed in the developing chick cerebellum predominantly in Purkinje cells. We detected the expression of SV2 in presynaptic terminals (mainly from climbing and mossy fibers) as soon as they are formed at embryonic day 16 in the inner molecular layer. Purkinje cells express Calbindin and GluR 2/3 in the soma and postsynaptically in the primary dendrites at this stage. With ongoing development, the pattern of SV2 expression follows the development of Purkinje cell dendrites in the molecular layer, suggesting a synaptic refinement of labeled climbing and later parallel fibers

Korrektur des LET-abhängigen Ansprechvermögens von faseroptischen Dosimetrie-Sonden

Viele Festkörperdosimetriesonden haben eine hohe räumliche und zeitliche Auflösung. Jedoch zeigt ihr Messsignal Quench-Effekte beim Einsatz in Protonenstrahlungsfeldern mit hohem linearen Energietransfer (LET). Ohne eine Korrektur dieses verminderten Messeffekts würde dies zu einer Unterschätzung der Dosis führen. In dieser Arbeit wurde ein Messsystem entwickelt, das auf einem an eine Lichtleitfaser gekoppelten sensitiven Volumen aus Berylliumoxid basiert, dessen Lumineszenzlicht während der Messung spektral geteilt wird. Dadurch entsteht eine zusätzliche Information, die eine Aussage über die Restreichweite und somit über den LET von Protonen am Messort ermöglicht. Es konnte gezeigt werden, dass das Signalverhältnis der beiden spektralen Anteile stark mit der Restreichweite von initial monoenergetischen Protonen korreliert. Auf dieser Basis wurde eine Korrekturfunktion implementiert, welche die Dosisunterschätzung für Protonen mit Anfangsenergien kleiner als 145 MeV gut ausgleicht. Eine beobachtete Abhängigkeit der Signalverhältnisbasierten Dosiskorrektur von der initialen Protonenenergie führt jedoch dazu, dass die Korrektur für initial höherenergetische Protonen bei hohem LET weiterhin eine unterschätzte Dosis liefert.:1 Einleitung 2 Physikalische Grundlagen zur Dosimetrie in Photonen- und Protonenfeldern 2.1 Strahlungsfeldgrößen 2.2 Wechselwirkungen von Photonen mit Materie 2.3 Wechselwirkungen geladener Teilchen mit Materie 2.4 Wichtige Größen der Dosimetrie und dosimetrische Konzepte 2.5 BeO-basierte Faser-Dosimetriesonden 3 Material und Methoden 3.1 Verwendetes Messsystem 3.2 Dosis-Kalibrierung des Messsystems im Photonen-Referenzfeld 3.3 Messungen im Protonenfeld an der UPTD 3.4 LET-abhängige Korrektur des Messeffekts 3.5 Verifikation 4 Ergebnisse 4.1 Dosis-Kalibrierung im Photonen-Referenzfeld 4.2 Messungen im Protonenfeld 4.3 LET-abhängige Korrektur des Messeffekts 4.4 Verifikation 5 Diskussion 6 ZusammenfassungMany solid dosemeters offer high spatial and temporal resolution. However, a common problem is their quenching in regions of high linear energy transfer (LET) during measurements in proton beams. This leads to reduced measurement signal, and thus, to dose underestimation. Hence, a dose correction is necessary. In this work a dosimetric system was developed which is based on a fiber coupled sensitive volume of beryllium oxide. Its radioluminescence signal is split into two spectral parts during measurement. Thereby one can obtain additional information that enables access to the values of residual range and LET of proton beams at the point of measurement. It could be shown that there exists a strong correlation between the signal ratio of both spectral parts of luminescence and the residual range of monoenergetic proton beams. Based on this, a correction function was implemented which allows for the adjustment of dose underestimation for measurements in proton beams of initial energies less than 145 MeV. Nevertheless, the signal ratio based correction function was observed to be dependent on the initial proton beam energy. Hence, the underestimation of the dose remains in the case of higher initial proton energies in regions of high LET.:1 Einleitung 2 Physikalische Grundlagen zur Dosimetrie in Photonen- und Protonenfeldern 2.1 Strahlungsfeldgrößen 2.2 Wechselwirkungen von Photonen mit Materie 2.3 Wechselwirkungen geladener Teilchen mit Materie 2.4 Wichtige Größen der Dosimetrie und dosimetrische Konzepte 2.5 BeO-basierte Faser-Dosimetriesonden 3 Material und Methoden 3.1 Verwendetes Messsystem 3.2 Dosis-Kalibrierung des Messsystems im Photonen-Referenzfeld 3.3 Messungen im Protonenfeld an der UPTD 3.4 LET-abhängige Korrektur des Messeffekts 3.5 Verifikation 4 Ergebnisse 4.1 Dosis-Kalibrierung im Photonen-Referenzfeld 4.2 Messungen im Protonenfeld 4.3 LET-abhängige Korrektur des Messeffekts 4.4 Verifikation 5 Diskussion 6 Zusammenfassun

The rebound effects of switching to vegetarianism

In order to reduce our environmental footprint, policy-makers have increasingly focused on influencing individual-level consumption choices. Recent years have seen a special focus on sustainable eating patterns, in particular the environmental benefits of a vegetarian diet. However, reliable conclusions on this issue need to take full-scale behavior changes into consideration. This can be achieved using the concept of the indirect rebound effect, which describes the amount of potential environmental improvements not realized due to the re-spending of expenditure saved during the initial behavior shift. This study aims to quantify the potential environmental savings stemming from the shift of an average Swedish consumer to vegetarianism, as well as the most likely rebound effects, in terms of both energy use and greenhouse gas emissions. To this end, it estimates Engel curves of 117 consumption goods, derives marginal expenditure shares from them, and links these values to environmental intensity indicators. Results indicate that switching to a vegetarian diet could save an average Swedish consumer 16% of the energy use and 20% of the greenhouse gas emissions related to their food and drink consumption. However, if they re-spend the saved income according to their current preferences, they would forego 96% of the potential energy savings and 49% of the greenhouse gas emission savings. These rebound effects are even higher for lower-income consumers, since they tend to respend on more environmentally intensive goods. Yet, the adverse effect could be tempered by simultaneously purchasing organic goods or by re-spending the money exclusively on services. Thus, consumption advice should shift to promoting holistic sustainable lifestyle changes

”Många skärmar blir det”

Lantarbetarnas arbetsförhållanden påverkas i allt större utsträckning av den digitalisering som accelererat sedan 1990-talet. Jordbruket har genomgått en stor omställning i och med införandet av digitala verktyg vilket resulterar i förändringar inom arbetsmiljö, arbetsbelastning och kunskapskrav. I den här uppsatsen undersöks hur lantarbetarnas arbetsförhållanden påverkas av digitaliseringen inom jordbruket. En kvalitativ studie har genomförts där sex lantarbetare vid sex storskaliga växtodlingsgårdar i Sverige intervjuats. Genom att belysa deras perspektiv skapas en djupare förståelse för konsekvenserna av denna omställning. Analysen genomförs med hjälp av begrepp kopplade till digitalisering, maktförskjutning och arbetsmiljö, samt teori baserad på Job Demand Resources-modellen (JD-R-modellen). Resultaten pekar på att lantarbetarna över lag upplever digitaliseringen inom jordbruket som en positiv utvecklingsfaktor. Särskilt vad gäller den fysiska arbetsmiljön samt arbetsbelastningen, vilka i stor utsträckning förbättrats. Områden där förbättringen framträder tydligast är komfort, säkerhet samt tidigare monotona arbetsuppgifter. Vad beträffar inverkan på den psykosociala arbetsmiljön finns något fler negativa tendenser. Till viss del beror försämringen av den psykosociala arbetsmiljön på övervakning samt de ökande kunskapskraven till följd av allt fler arbetsmoment som involverar digitala verktyg.The working conditions of agricultural workers are increasingly influenced by the digitalization that has accelerated since the 1990s. Agriculture has undergone significant transformation with the introduction of digital tools, resulting in changes in the work environment, workload, and skill requirements. This thesis examines how the working conditions of agricultural workers are affected by digitalization in agriculture. A qualitative study was conducted, in which six agricultural workers from six large-scale crop farms in Sweden were interviewed. By highlighting their perspectives, a deeper understanding of the consequences of this transformation is gained. The analysis is carried out using concepts related to digitalization, power shifts, and the work environment, as well as theory based on the Job Demand Resources model. The results indicate that, overall, agricultural workers perceive digitalization in agriculture as a positive developmental factor. Particularly in terms of the physical work environment and workload, significant improvements have been made. Areas where the improvements are most evident include comfort, safety, and previously monotonous tasks. However, regarding the impact on the psychosocial work environment, there are slightly more negative tendencies. The deterioration of the psychosocial work environment is partly due to surveillance and the increasing knowledge requirements resulting from the growing number of tasks involving digital tools

Self Assembled II-VI Magnetic Quantum Dot as a Voltage-Controlled Spin-Filter

A key element in the emergence of a full spintronics technology is the development of voltage controlled spin filters to selectively inject carriers of desired spin into semiconductors. We previously demonstrated a prototype of such a device using a II-VI dilute-magnetic semiconductor quantum well which, however, still required an external magnetic field to generate the level splitting. Recent theory suggests that spin selection may be achievable in II-VI paramagnetic semiconductors without external magnetic field through local carrier mediated ferromagnetic interactions. We present the first experimental observation of such an effect using non-magnetic CdSe self-assembled quantum dots in a paramagnetic (Zn,Be,Mn)Se barrier.Comment: 4 pages, 4 figure