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Nature uses replication to amplify the information necessary for the intricate structures vital for life. Despite some successes with pure nucleotide structures, constructing synthetic microscale systems capable of replication remains largely out of reach. Here, a functioning strategy is shown for the replication of microscale particle assemblies using DNA-coated colloids. By positioning DNA-functionalized colloids using capillary forces and embedding them into a polymer layer, programmable sequences of patchy particles are created that act as a primer and offer precise binding of complementary particles from suspension. The strings of complementary colloids are cross-linked, released from the primer, and purified via flow cytometric sorting to achieve a purity of up to 81% of the replicated sequences. The replication of strings of up to five colloids and non-linear shapes is demonstrated with particles of different sizes and materials. Furthermore, a pathway for exponential self-replication is outlined, including preliminary data that shows the transfer of patches and binding of a second-generation of assemblies from suspension.
Sujet(s)
Colloïdes , ADN , Colloïdes/composition chimique , ADN/composition chimique , Cytométrie en flux , Réplication de l'ADNRÉSUMÉ
Resistive heating elements can be of particular interest for many applications, such as e-skin. In this study, soft heating elements were developed by combining thermoplastic polyurethane (TPU) with carbon black. In contrast to previous studies on thermoplastic polymer-based thermistors, the heating elements could endure elongations above 100%. Due to the high melting point of the TPU and the carbon filler, the thermistors could be heated up to 180°C without significant deformation. The heating elements were extruded on TPU substrates using material extrusion additive manufacturing in one-step process. Self-regulating behavior to control the maximum temperature was achieved with the application of two different voltages (20 and 25 V) and different current thresholds, between 100 and 800 mA. The heating performance was adjusted by changing the geometry of the sensing elements; an increase in cross section resulted in a lower current density and lower temperature. For the heating elements, variation of the additive manufacturing parameters such as offset, layer height, nozzle speed, and extrusion multiplier resulted in a different width/height aspect ratio of the cross section of the extruded lines, affecting the initial resistivity of the thermistor. Orientation of the carbon filler during extrusion process is one reason for the small change of the longitudinal conductivity of the heating elements. The resulting skin with the integrated heating elements allowed the possibility to perform the in situ heating for the localized healing of structural damage, while maintaining the softness required for the application of soft robotic electronic skin.
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Colloidal particles are considered to be essential building blocks for creating innovative self-assembled and active materials, for which complexity beyond that of compositionally uniform particles is key. However, synthesizing complex, multi-material colloids remains a challenge, often resulting in heterogeneous populations that require post-synthesis purification. Leveraging advances brought forward in the purification of biological samples, here we apply fluorescence-activated cell sorting (FACS) to sort colloidal clusters synthesized through capillary assembly. Our results demonstrate the effectiveness of FACS in sorting clusters based on size, shape, and composition. Notably, we achieve a sorting purity of up to 97% for clusters composed of up to 9 particles, albeit observing a decline in purity with increasing cluster size. Additionally, dimers of different colloids can be purified to over 97%, while linear and triangular trimers can be separated with up to 88% purity. This work underscores the potential of FACS as a promising and little-used tool in colloidal science to support the development of increasingly more intricate particle-based building blocks.
Sujet(s)
Colloïdes , Polymères , Cytométrie en flux/méthodesRÉSUMÉ
In February 2022, Swiss citizens agreed to modify the Swiss Constitution to ban tobacco advertising reaching children and adolescents. This case study analyses the arguments used by both opponents and supporters of the constitutional amendment. Opponents argued that the proposed regulation went too far, threatened the economy, restricted personal freedom, was superfluous as the current law already protected youth and that it opened the door to marketing bans of other harmful products. Proponents focused on youth protection and invoked the burden of smoking on public health and the fact that advertising bans are an effective evidence-based measure. A comparison with previous campaigns to ban tobacco advertising that had failed suggests factors accounting for the positive vote in 2022. These include the strategic framing of youth protection, the separation of tobacco from other issues (such as alcohol advertising), the deteriorating image of the tobacco industry and the ability of the proponents to mobilise a broad coalition of health and youth organisations, with improved funding and communication. The lessons may be instructive for other campaigns seeking to regulate commercial determinants of health.
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INTRODUCTION: Tobacco cigarette taxes aim at reducing smoking, but smokers are still dependent on nicotine and need safe and cheap alternatives. As the costs play a role in the product chosen, we compared standardized nicotine costs across products and countries. METHODS: We gathered prices of tobacco cigarettes, heated tobacco products (HTP), pharmaceutical nicotine replacement therapy (pNRT) gums, snus, and open and closed electronic nicotine delivery systems (ENDS) in 6 countries (Switzerland, Germany, USA, Sweden, France, UK) in 2019. We compared the cost of a pack of cigarettes in Switzerland to the cost of equivalent doses of nicotine delivered by other products and across countries, normalizing to purchasing power GDP per capita to compute relative adjusted costs (RACs). RESULTS: Adjusted tobacco cigarette cost was lowest in Switzerland, Germany, and Sweden; RAC for pNRT was 1.1 in Switzerland and 1.0 in Germany. In France and the UK, RACs for cigarettes were 1.5 and 2.1, while for pNRT they were cheaper (RAC: 0.04). In Switzerland, snus/nicotine pouches were the cheapest form of nicotine delivery (RAC: 0.2), open ENDS were a low-cost option for nicotine delivery in all countries (RAC: 0.2-0.3), and HTP cost more than regular tobacco products in most countries. CONCLUSIONS: We found broad differences in costs of nicotine according to countries and products. This should be considered in future studies on smoking prevalence and in public health efforts.
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OBJECTIVE: This paper explores transnational tobacco companies' (TTCs) long-term policy influence strategies using two case studies, harm reduction and illicit tobacco, to identify lessons for the tobacco control movement and wider efforts to address the commercial determinants of health. METHODS: Evidence from a broad combination of sources including leaked documents and findings from over two decades of TTC monitoring were reviewed for each case study and categorised using the Policy Dystopia Model, focusing on the primary discursive strategy and key instrumental (action-based) strategies used. RESULTS: In both case studies, TTCs seek to advance their interests by engaging primarily in reputation management, coalition management and information management strategies over the long-term to propagate their over-riding discursive strategy-'we've changed, we are part of the solution'-despite clear evidence from both case studies that this is not the case. These strategies are globally coordinated and attempt primarily to reshape norms towards TTC involvement in tobacco control policy and delivery. Findings also suggest that industry denormalisation and the advent of Article 5.3 have led to the TTCs growing use of increasingly complex and opaque 'webs of influence'. CONCLUSIONS: The tobacco control community must develop its own proactive long-term strategies which should include industry denormalisation, new ways to fund research that reduce industry control, and improved transparency measures for research and policy. These findings, including TTC adaptations to Article 5.3, also indicate the need for more structural solutions, addressing corporate power and the underlying political and economic system. These lessons can be applied to other unhealthy commodity industries.
Sujet(s)
Industrie du tabac , Produits du tabac , Humains , Politique publique , Nicotiana , Usage de tabacRÉSUMÉ
Nicotine industry: harm reduction, an exclusively financial objective The knowledge of tobacco smoking health effects, combined with the implementation of measures efficient on its use, leads to tobacco sale reduction with tobacco industry financial losses that, in order to survive, has to recruit new young consumers, and maintain current smokers' use. The industry promotes a new way for tobacco use that, according to it, would reduce harm: heat-not-burn tobacco. But, there is currently no independent scientific proof for such a harm reduction. In the meantime, it promotes a confusion among electronic cigarettes and heat-not-burn tobacco. Heat-not-burn tobacco is promoted via foundations, NGOs, prestigious third parties, mechanic sports financing, and publicity with a strong marketing targeting young people through social networks. The current French regulation concerning smoked tobacco, including plain pack and high taxes, doesn't apply on heat-not-burn tobacco.
"Industrie de la nicotine : réduction des risques, un objectif exclusivement financier La connaissance des risques liés au tabac fumé associée à la prise de mesures efficaces pour réduire sa consommation conduit à la baisse des ventes avec chute des profits de l'industrie du tabac qui, pour survivre, doit recruter de nouveaux jeunes consommateurs et maintenir les usagers actuels dans leur consommation. L'industrie propose un nouveau mode de consommation qui, selon elle, permettrait de réduire les risques : le tabac chauffé. Or, aucune preuve scientifique indépendante n'existe d'une telle réduction de risques. En même temps, elle entretient la confusion entre cigarettes électroniques et tabac chauffé. Le tabac chauffé est promu par le biais de fondations, associations, relais prestigieux, financement des sports mécaniques et publicités avec un marketing intense ciblant les jeunes par les réseaux sociaux. La réglementation française concernant le tabac fumé ne s'applique pas au tabac chauffé, lui permettant ainsi d'échapper au paquet neutre et autorisant des profits majeurs par taxation plus légère."
Sujet(s)
Dispositifs électroniques d'administration de nicotine , Industrie du tabac , Produits du tabac , Adolescent , Humains , Nicotine , Comportement de réduction des risques , Fumer du tabacRÉSUMÉ
QUESTION UNDER STUDY: Surveys on tobacco consumption represent an important decision aid for public health policy related to smoking. Although Switzerland's tobacco control policies and regulations are among the weakest, its reported smoking prevalence is among the lowest in Europe. However, there appears to be a discrepancy between reported prevalence and aggregate data on national cigarette consumption. Our purpose was to closely look at this discrepancy and study its significance. METHODS: Calculation of national aggregate tobacco consumption by Switzerland's resident population for the years 2012 to 2015 and comparison with reported consumption derived from survey results on smoking prevalence and intensity. Comparison with similar data for France for year 2014. Evaluation of several hypotheses to explain the discrepancy between survey results and national aggregate consumption data. RESULTS: There was a large discrepancy of about 45% between reported smoking consumption implied by survey results and estimated actual consumption derived from aggregate data on sales. Whereas survey results suggest smoking prevalence in Switzerland to be around 25% and rather stable during the period 2012 to 2015, true prevalence could be greater than 31%. CONCLUSION: The results of surveys aiming to estimate smoking prevalence and intensity in Switzerland may substantially suffer from underreporting, misreporting and sampling bias. Survey methodology needs to be examined to see whether such reporting discrepancy can be reduced.
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Collecte de données/méthodes , Surveillance de la population , Fumer/épidémiologie , Femelle , Humains , Mâle , Prévalence , Politique publique , Biais de sélection , Fumer/effets indésirables , SuisseRÉSUMÉ
INTRODUCTION: Our objective was to re-analyse the data used in an industry-funded working paper to study the effect of plain packaging on youth smoking prevalence in Australia, allowing for other tobacco control measures introduced over the period 2001-2013, and using a more appropriate method of analysis. METHODS: Monthly smoking prevalence and sample sizes from repeat cross-sectional surveys were reconstructed from the working paper by reverse engineering of the industry-presented data, and analysed as a time series using logistic regression. Power analysis presented in the industry-funded working paper was re-calculated. RESULTS: Smoking prevalence among minors in Australia declined from 11.6% to 5.6% over the 13-year period examined; an overall 52% relative reduction or an average annual reduction of 5.5% (95% confidence interval 4.6% to 6.4%). There was a 12.1% (-4.8% to 26.2%) relative reduction in smoking prevalence when plain packaging was introduced, though the reduction was not statistically significant. Re-calculated power values were much lower than those reported in the industry-funded paper, confirming the inconclusiveness of its findings, as pointed out in previous critiques. CONCLUSIONS: Our findings suggest a decline of smoking prevalence in minors following the introduction of plain packaging in Australia. They differ substantially from those presented in an industry-funded study on the effects of plain packaging on smoking prevalence in minors in Australia, which used the same data.
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In this commentary we consider the validity of tobacco industry-funded research on the effects of standardised packaging in Australia. As the first country to introduce standardised packs, Australia is closely watched, and Philip Morris International has recently funded two studies into the impact of the measure on smoking prevalence. Both of these papers are flawed in conception as well as design but have nonetheless been widely publicised as cautionary tales against standardised pack legislation. Specifically, we focus on the low statistical significance of the analytical methods used and the assumption that standardised packaging should have an immediate large impact on smoking prevalence.
Sujet(s)
Emballage de produit/normes , Fumer/épidémiologie , Industrie du tabac/normes , Produits du tabac , Australie , Interprétation statistique de données , Humains , Recherche/économie , Recherche/normes , Plan de recherche/normes , Soutien financier à la recherche comme sujetRÉSUMÉ
The ill effects of second-hand smoke are now well documented. To protect the population from exposure to tobacco smoke, comprehensive smoking bans are necessary as expressed in the WHO Framework Convention on Tobacco Control and its guidelines. Switzerland has only a partial smoking ban full of exceptions which has been in effect since 2010, which reproduces the so-called Spanish model. In September 2012, the Swiss citizens refused a proposal for a more comprehensive ban. This case study examines the reasons behind this rejection and draws some lessons that can be learnt from it.
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Pollution de l'air intérieur/législation et jurisprudence , Attitude envers la santé , Politique , Fumer/législation et jurisprudence , Pollution par la fumée de tabac/législation et jurisprudence , Pollution de l'air intérieur/prévention et contrôle , Connaissances, attitudes et pratiques en santé , Politique de santé , Humains , Fumer/économie , Suisse , Pollution par la fumée de tabac/prévention et contrôleRÉSUMÉ
BACKGROUND: Smoking is thought to produce an appetite-suppressing effect by many smokers. Thus, the fear of body weight gain often outweighs the perception of health benefits associated with smoking cessation, particularly in adolescents. We examined whether the tobacco industry played a role in appetite and body weight control related to smoking and smoking cessation. METHODS: We performed a systematic search within the archives of six major US and UK tobacco companies (American Tobacco, Philip Morris, RJ Reynolds, Lorillard, Brown & Williamson and British American Tobacco) that were Defendants in tobacco litigation settled in 1998. Findings are dated from 1949 to 1999. RESULTS: The documents revealed the strategies planned and used by the industry to enhance effects of smoking on weight and appetite, mostly by chemical modifications of cigarettes contents. Appetite-suppressant molecules, such as tartaric acid and 2-acetylpyridine were added to some cigarettes. CONCLUSION: These tobacco companies played an active and not disclaimed role in the anti-appetite effects of smoking, at least in the past, by adding appetite-suppressant molecules into their cigarettes.