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Evaluation of the applicability of GARDskin to predict skin sensitizers in extracts from medical device materials
No full textBiocompatibility testing of medical devices is governed by the ISO 10993 series of standards and includes evaluation of skin sensitization potential of the final product. A majority of all medical devices are tested using in vivo methods, largely due to the lack of in vitro methods validated within the applicability domain of solid materials. The GARDskin method for assessment of chemical skin sensitizers is a validated method included in the OECD Test Guideline 442E, based on evaluation of transcriptional patterns of an endpoint-specific genomic biomarker signature in a dendritic cell-like cell, following test chemical exposure. The current study aimed to evaluate the applicability of GARDskin for the purpose of testing solid materials by incorporation of extraction procedures described in ISO 10993-12:2021, as well as to demonstrate the functionality of the proposed protocols, by testing of custom-made materials spiked with sensitizing agents. It was shown that GARDskin is compatible with both polar and non-polar extraction vehicles frequently used for the purpose of medical device biological testing. Further, exploring three different material types spiked with up to four different sensitizing agents, as well as three unspiked control materials and commercial reference products, it was shown that the method correctly classified all evaluated test materials. Taken together, the data presented suggest that GARDskin may constitute a valid alternative to in vivo experimentation for the purpose of skin sensitization assessment of medical devices. The reported study was funded in its entirety by SenzaGen AB.</p
A novel model for solid fuel combustion with particle migration
No full textSolid fuel conversion in a fixed-bed is a challenging modelling task due to different time and length scales and the importance of heat transfer mechanisms. The current study aims to propose a novel model that can capture all the main features of the conversion of fuel bed while maintaining a moderate computational cost. The model is based on the commonly applied porous media approach, which describes the solid phase using an Eulerian framework. A layered particle submodel with four types of solids, wet wood, dry wood, char, and ash, is implemented to account for different conversion stages. At each computational cell, a matrix is used to record the information on all the properties of the four types of solids, including the number and volume of particles. The model allows the exchange of particles between cells, thus capable of simulating the motion of the fuel bed during conversion, such as bed collapsing. In addition, the new model can efficiently calculate heat transfer between particles and particles and fluid in each computational cell. The proposed model is validated against a series of experiments on biomass conversion in a rectangular fixed-bed combustor operated in a counter-current mode with various air supply rates. Good agreement with experiments was found even at the limited combustion regime. With the overall low computational cost generated by the bed model, the proposed model framework has the potential to efficiently simulate a wide range of solid fuel conversion processes at a large scale, not only in fixed-beds but also in moving beds and rotary kilns. The authors acknowledge support from the Research Council of Norway and a number of industrial partners through the BioCarbUp project (294679) and BioSynGas project (319723).</p
Spatial distribution of active compounds in stratum corneum—partitioning between corneocytes and lipid matrix
No full textThe interaction of active substances with molecular structures in stratum corneum (SC) is crucial for the efficacy and safety of cosmetic formulations and topical drugs. However, the molecular architecture of SC is highly complex and methods to unambiguously localize exogenous molecules within SC are lacking. Consequently, little is known about the distribution of actives within SC, and proposed penetration mechanisms through SC are typically limited to simple diffusion via a tortuous (lipid only) or transverse (across corneocytes and lipid matrix) pathway. In this work, 3D mass spectrometry imaging is used to determine the spatial distributions of four active substances at subcellular resolution in SC, including partitioning between the corneocytes and the intercellular lipid matrix. The results indicate that caffeine, 2-methyl resorcinol and oxybenzone are homogeneously distributed in the corneocytes but largely absent in the lipid matrix, despite considerable differences in lipophilicity. In contrast, the distribution- of jasmonic acid derivative is more inhomogeneous and indicates considerable localization to both the lipid phase and the corneocytes
Att utveckla och implementera cybersäkerhetspolicy : Lärdomar från den finansiella sektorn
No full textModern society is increasingly dependent on digital services, making their dependability a top priority. But while there is a consensus that cybersecurity is important, there is no corresponding agreement on the true extent of the problem, the most effective countermeasures, or the proper division of labor and responsibilities. This makes cybersecurity policy very difficult. This article addresses this issue based on observations and experiences from a period of guest research at the Swedish Financial Supervisory Authority (Finansinspektionen), which made it possible to study how cybersecurity policy is developed and implemented in the Swedish financial sector. Observations include policy implementation challenges related to squaring different roles and perspectives mandated by different laws, and to collaboration between independent government authorities, but also policy development challenges: How can the full range of perspectives and tools be included in cybersecurity policy development? As Sweden now revises its cybersecurity policy, this is a key issue.Den aktuella studien är finansierad av Stiftelsen för Strategisk Forskning (avtalsnummer SM22-0057)</p
Advancing LWIR FSO communication through high-speed multilevel signals and directly modulated quantum cascade lasers
No full textThis study investigates the potential of long-wave infrared (LWIR) free-space optical (FSO) transmission using multilevel signals to achieve high spectral efficiency. The FSO transmission system includes a directly modulated-quantum cascade laser (DM-QCL) operating at 9.1 µm and a mercury cadmium telluride (MCT) detector. The laser operated at the temperature settings of 15°C and 20°C. The experiment was conducted over a distance of 1 m and in a lab as a controlled environment. We conduct small-signal characterization of the system, including the DM-QCL chip and MCT detector, evaluating the end-to-end response of both components and all associated electrical elements. For large-signal characterization, we employ a range of modulation formats, including non-return-to-zero on-off keying (NRZ-OOK), 4-level pulse amplitude modulation (PAM4), and 6-level PAM (PAM6), with the objective of optimizing both the bit rate and spectral efficiency of the FSO transmission by applying pre- and post-processing equalization. At 15°C, the studied LWIR FSO system achieves net bitrates of 15 Gbps with an NRZ-OOK signal and 16.9 Gbps with PAM4, both below the 6.25% overhead hard decision-forward error correction (6.25%-OH HD-FEC) limit, and 10 Gbps NRZ-OOK below the 2.7% overhead Reed-Solomon RS(528,514) pre-FEC (KR-FEC limit). At 20°C, we obtained net bitrates of 14.1 Gbps with NRZ-OOK, 16.9 Gbps with PAM4, and 16.4 Gbps with PAM6. Furthermore, we evaluate the BER performance as a function of the decision feedback equalization (DFE) tap number to explore the role of equalization in enhancing signal fidelity and reducing errors in FSO transmission. Our findings accentuate the competitive potential of DM-QCL and MCT detector-based FSO transceivers with digital equalization for the next generation of FSO communication systems. Horizon 2020 Framework Programme cFLOW project (828893); Vetenskapsr\u00E5det (2019-05197); Project \u2019BRAIN\u2019 (2022-04798); EU COST Action CA19111 NEWFOCUS; The LZP FLPP Project \u2019MIR-FAST\u2019 (lzp-2023-1-0503); The Strategic innovation program smarter electronic systems - a joint venture by Vinnona, Forms and the Swedish Energy Agency A-FRONTHAUL Project (2023-00659).</p
The fate of hazardous textile pollutants in an upcycling process for post-consumer garments
No full textThe environmental impact is a strong incentive for the development of upcycling processes for textile waste. However, toxic chemicals may occur in both brand-new textiles and post-consumer garments, and the chemical transfer in such routes is important to investigate. The present study applied non-target screening and quantification with liquid chromatography/mass spectrometry to follow the fate of hazardous chemicals from post-consumer polycotton garments to a new material, cellulose nanocrystals, in a chemical upcycling utilizing strongly acidic conditions. The majority of hazardous chemicals detected within the process were found to be transferred to a residual of polyester material and not to the enriched cellulose. However, phthalates were found to be mainly attached to the cellulose nanocrystals. The detected total concentration, in this case, was below 5 μg/g, at least 200 times lower than the limit set by the European Union. This indicates the importance of monitoring and controlling the phthalate content in the starting material of the process, i.e., the post-consumer garments. The chemical release into the process waste effluent could be estimated based on water solubility data for chemicals under the applied conditions. Three compounds, the water-repellent substance perfluorooctanesulfonic acid and the dyes Crystal Violet and Victoria Pure Blue, were almost entirely transferred into the process waste effluent. Although the levels detected were very low in the present pilot process, their presence eventually indicates the need for wastewater purification at further upscaling, depending on the exposure and dose in relation to toxicological relevant thresholds. he authors thank the following funding agencies for financial support: Swedish Foundation for Strategic Environmental Research (Mistra: project Mistra SafeChem, project number 2018/11) and the Swedish Research Council for Sustainable Development, Formas (Grant No: 2021-01540).</p
Transforming post-consumer cotton waste textiles into viscose staple fiber using hydrated zinc chloride
No full textLarge amounts of cellulose-based waste textiles are generated every year, yet little is done to recycle this waste. Alternatives such as fiber-to-fiber recycling, where a significant part of the value of the waste textiles is recovered, are attractive possibilities. In this study, we have investigated the viability of using hydrated zinc chloride (ZnCl2·4H2O) as a solvent and swelling agent to convert cotton waste textiles (the most abundant cellulose-based waste textile) into a dissolving pulp that can be used as raw material for the production and spinning of viscose fibers. The solvent produced an accessible dissolving pulp and exhibited excellent recyclability, maintaining good dissolving power even after repeated recycling. The dissolving pulp was subsequently used to produce viscose dope, a spinning solution which was spun and cut into viscose staple fibers. The viscose dope exhibited good properties (moderate filter clogging value and gamma number), and the resulting staple fibers were strong and of good quality (high linear density, elongation, and tenacity). These results illustrate the potential of using hydrated zinc chloride for the production of viscose grade dissolving pulp from cotton waste textiles. Open access funding provided by Lund University. This work was funded by the Swedish Energy Agency (project number 51217–1) and ShareTex AB. ShareTex AB financed the zinc chloride used in this work. Furthermore, ShareTex AB also funded the treatment of cotton textile waste with zinc chloride as well as the experiments on recycling of zinc chloride. The rest was funded by the Swedish Energy Agency.</p
Experimental study on the maximum ceiling gas temperature driven by double fires in a tunnel with natural ventilation
No full textThe maximum gas temperature below the ceiling is an important parameter for tunnel safety. The present study analyzed the characteristics of the maximum excess ceiling gas temperature driven by double fire sources in a naturally ventilated tunnel. A series of small-scale tunnel fire experiments were carried out with different fire separation distances and heat release rates. Theoretical analysis based on the equivalent virtual origin was also performed. The results showed that there exists only one peak gas temperature when the two fire plumes are merged before reaching the ceiling, while two peak gas temperatures can be observed when the two fire plumes are completely separated. The maximum excess gas temperature below the tunnel ceiling gradually decreases with an increasing fire separation distance in the plume merging region (S < Scp). When the fire separation distance increases further (S > Scp), the effect of the fire separation distance on the maximum gas temperature below the ceiling is very limited. Furthermore, a model using an equivalent fire source was proposed to predict the maximum excess gas temperature below the ceiling, considering different plume merging states. The present study contributes to the understanding of the maximum excess gas temperature characteristics of the smoke flow driven by double fires with an equal heat release rate in naturally ventilated tunnels. This work was financially supported by National Key Research and Development Program of China (No. 2022YFC3005201 ), the Tunnel and Underground Safety Center (TUSC), the Swedish Fire Research Board (BRANDFORSK), Youth Innovation Promotion Association CAS (No. CX2320007001 ), Fundamental Research Funds for the Central Universities under Grants (No. WK2320000048 and No. WK2320000056 ) and USTC Tang Scholar, which are greatly acknowledged.</p
Livscykelanalys av stenskottsåtgärder
No full textSyftet med denna studie var att utvärdera miljöpåverkan från åtgärder som stenskottsskador på vindrutor kan ge upphov till i form av byte respektive reparation av en ruta. Studien omfattade hela livscykeln från vagga till grav med fokus på klimatpåverkan, men inkluderade även fler miljöpåverkanskategorier. Den funktionella enheten definierades som att åtgärda en vindruta på 15 kg med stenskottsskada genom antingen reparation eller byte av rutan. För reparation inkluderades transport av fordon till och från verkstad samt energi- och materialåtgång under själva reparationen i verkstaden. Byte omfattade i sin tur transport av fordon till och från verkstad, tillverkning av ny ruta, transport av ny ruta till verkstad, energi- och materialåtgång vid själva bytet, samt avfallshantering av den utbytta rutan. Resultaten från denna livscykelanalys visade på tydliga miljömässiga fördelar med att reparera jämfört med att byta en stenskottsskadad vindruta. Baserat på de grundantaganden som gjordes beräknades ett byte ge upphov till en klimatpåverkan på omkring 88 kg CO2-ekv och en reparation omkring 18 kg CO2-ekv. Det innebär en besparing på cirka 70 kg CO2-ekv och att en ruta kan repareras fyra gånger innan klimatpåverkan överstiger den vid ett byte. Majoriteten av påverkan vid ett byte tillskrevs tillverkningen av rutan (ca 56%), följt av transporten av fordonet till och från verkstaden (ca 20%), samt transporten av rutan till verkstaden (ca 14%). Avfallshanteringen och själva bytet på verkstaden hade båda liten påverkan. För en reparation orsakades nästan hela påverkan av transporten av fordonet till och från verkstaden (ca 97%), medan själva reparationsprocessen gav försumbart bidrag. Om flera reparationer genomförs för att undvika ett byte är det därför främst transporten av fordonet till och från verkstaden som är viktig att beakta och minimera för att undvika att reparation ger högre påverkan än byte. En liknande trend som för klimatpåverkan observerades även för miljöpåverkanskategorierna försurning, marin övergödning, terrester övergödning, fotokemisk ozonbildning, fossil resursanvändning och vattenanvändning, där en reparation motsvarade 19-30% av påverkan från ett byte. Övriga studerade kategorier i form av sötvattenövergödning, ozonförtunning och resursanvändning av metaller och mineral visade en mindre skillnad, där en reparation motsvarade 45-52% av påverkan från ett byte. Den mindre skillnaden orsakades av transporten till och från verkstaden, som antogs vara samma oavsett åtgärd. Sammanfattningsvis pekade dessa resultat på att åtgärder mot att reducera klimatpåverkan också verkar ge positiva effekter på andra miljöaspekter. Känslighetsanalyserna som genomfördes identifierade transporten av fordonet till och från verkstaden som en viktig faktor att beakta. Distansen hade stor betydelse för den totala påverkan, men även fordonstyp och drivlina. Transporten av en ny ruta till verkstaden identifierades också som en viktig parameter att ta hänsyn till. Denna transport påverkades i sin tur av vikten på rutan, ytterligare en parameter med signifikant påverkan på resultatet vid byte av ruta. Vidare visade känslighetsanalyserna att så länge en energimix med relativt låg klimatpåverkan används, som exempelvis en svensk, har både själva bytes- och reparationsprocessen liten påverkan. Beträffande avfallshanteringen identifierades viss potential i att återvinna glaset genom den systemexpansion som genomfördes, något som motiverar fortsatt strävan mot återvinning av vindrutor. I övrigt syntes inga stora skillnader i resultat beroende på hur den utbytta rutan avfallshanteras, givet den cut-off-metodik som studien byggde på
Processkartläggning och processdesign för hållbar dagvattenhantering – En metod för stärkt samverkan
No full textDagvattenhantering kvartersmark</p