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Cross-sections of cell shapes in a tissue monolayer typically resemble a tiling of convex polygons. Yet, examples exist where the polygons are not convex with curved cell–cell interfaces, as seen in the adaxial epidermis. To date, two-dimensional vertex models predicting the structure and mechanics of cell monolayers have been mostly limited to convex polygons. To overcome this limitation, we introduce a framework to study curvy cell–cell interfaces at the subcellular scale within vertex models by using a parametrized curve between vertices that is expanded in a Fourier series and whose coefficients represent additional degrees of freedom. This extension to non-convex polygons allows for cells with the same shape index, or dimensionless perimeter, to be, for example, either elongated or globular with lobes. In the presence of applied, anisotropic stresses, we find that local, subcellular curvature or buckling can be energetically more favourable than larger scale deformations involving groups of cells. Inspired by recent experiments, we also find that local, subcellular curvature at cell–cell interfaces emerges in a group of cells in response to the swelling of additional cells surrounding the group. Our framework, therefore, can account for a wider array of multicellular responses to constraints in the tissue environment.

Developing efficient and selective strategies to approach complex architectures containing (multi)stereogenic centers has been a long-standing synthetic challenge in both academia and industry. Catalytic cascade reactions represent a powerful means of rapidly leveraging molecular complexity from simple feedstocks. Unfortunately, carrying out cascade Heck-type reactions involving unactivated (tertiary) alkyl halides remains an unmet challenge owing to unavoidable β-hydride elimination. Herein, we show that a modular, practical, and general palladium-catalyzed, radical three-component coupling can indeed overcome the aforementioned limitations through an interrupted Heck/allylic substitution sequence mediated by visible light. Selective 1,4-difunctionalization of unactivated 1,3-dienes, such as butadiene, has been achieved by employing different commercially available nitrogen-, oxygen-, sulfur-, or carbon-based nucleophiles and unactivated alkyl bromides (>130 examples, mostly >95:5 E/Z, >20:1 rr). Sequential C(sp3)–C(sp3) and C–X (N, O, S) bonds have been constructed efficiently with a broad scope and high functional group tolerance. The flexibility and versatility of the strategy have been illustrated in a gram-scale reaction and streamlined syntheses of complex ether, sulfone, and tertiary amine products, some of which would be difficult to access via currently established methods.

sp3-hybridized attached-rings are common motifs in secondary metabolites and represent tetrahedral equivalents to the biaryl substructures that overpopulate synthetic libraries. Few methods are available that can link fully substituted carbon atoms of two rings with stereocontrol. Here we have developed a stereoselective, heteroselective butenolide coupling that exhibits an unusually fast rate of C–C bond formation driven by exquisite complementarity of the reacting π systems. Heterodimerization generates a compound collection with topological complexity and diverse principal moments of inertia. The special status of the sp3–sp3attached-ring motif is demonstrated in a high-throughput screen for inhibitors of the cyclic GMP-AMP synthase/stimulator of interferon genes pathway, which recruited these butenolide heterodimers from a field of 250,000 compounds. The driving forces underlying this general attached-ring coupling identify a novel paradigm for the accession of wider natural product chemical space, accelerating the discovery of selective lead compounds.

Herein, we report the synthesis of protected 1,2-amino alcohols starting from carbonyl compounds and α-silyl amines. The reaction is enabled by a Cr/photoredox dual catalytic system that allows the in situgeneration of α-amino carbanion equivalents which act as nucleophiles. The unique nature of this reaction was demonstrated through the aminoalkylation of ketones and an acyl silane, classes of electrophiles that were previously unreactive toward addition of alkyl-Cr reagents. Overall, this reaction broadens the scope of Cr-mediated carbonyl alkylations and discloses an underexplored retrosynthetic strategy for the synthesis of 1,2-amino alcohols.

Herein we report on the development of an MS tag screening strategy that accelerates the discovery of photocatalytic reactions. By efficiently combining mechanism- and reaction-based screening dimensions, the respective advantages of each strategy were retained, whereas the drawbacks inherent to each screening approach could be eliminated. Applying this approach led to the discovery of a mild photosensitized decarboxylative hydrazide synthesis from mesoionic sydnones and carboxylic acids as starting materials.

This study illustrates the high complexity of phosphorus-based decomposition products in thermally treated state-of-the-art lithium ion battery (LIB) electrolytes. Liquid chromatographic techniques hyphenated to ion trap time-of-flight mass spectrometry reveal 122 different organophosphate (OP) and organofluorophosphate (OFP) species, the majority of which are not reported in the literature so far. The application of hydrophilic interaction liquid chromatography and reversed-phase chromatography enables the investigation of the acidic as well as nonacidic spectrum of aging products. Furthermore, the generation of high structure certainty by consideration of (i) mass accuracy of the precursor ions and subsequent MS2/3fragments, (ii) fragment intensity distribution in the mass spectra, and (iii) retention times in hydrophilic interaction liquid chromatography (HILIC) and reversed-phase (RP) separation allows a target analysis of further work in the LIB electrolyte context. In an ethyl methyl carbonate-based battery electrolyte, 82 OP compounds, 27 OFPs, and 13 cyclic O(F)Ps are identified. Additionally, the formation of 8-membered organo(fluoro)phosphate rings in lithium ion battery electrolytes is reported for the first time. Since the high toxic potential of organo(fluoro)phosphates has emerged interest in safety assessments of electrolytes, the knowledge of possibly formed substances supports further quantification approaches and toxicological assessments compared to nontarget investigations.

Herein, we report the redox-neutral allylation of aldehydes with readily available electron-rich allyl (hetero-) arenes, β-alkyl styrenes and allyl-diarylamines. This process was enabled by the combination of photoredox and chromium catalysis, which allowed a range of homoallylic alcohols to be prepared with high levels of selectivity for the antidiastereomer. Mechanistic investigations support the formation of an allyl chromium intermediate from allylic C(sp3)–H bonds and thus significantly extends the scope of the venerable Nozaki–Hiyama–Kishi reaction.

Cell migration is important in many biological processes, including embryonic development, cancer metastasis and wound healing. In these tissues, a cell’s motion is often strongly constrained by its neighbours, leading to glassy dynamics. Although self-propelled particle models exhibit a density-driven glass transition, this does not explain liquid-to-solid transitions in confluent tissues, where there are no gaps between cells and therefore the density is constant. Here we demonstrate the existence of a new type of rigidity transition that occurs in the well-studied vertex model for confluent tissue monolayers at constant density. We find that the onset of rigidity is governed by a model parameter that encodes single-cell properties such as cell–cell adhesion and cortical tension, providing an explanation for liquid-to-solid transitions in confluent tissues and making testable predictions about how these transitions differ from those in particulate matter.

The real-time knowledge of industrial laser power and energy profile distribution into beam gives important informations with the object of operation control like welding or thermal treatments, and even indispensable to control the system. With a view to show-up the feasibility of such an operation, we have executed some tests with differents systems able to measure the beam global power and its energy spatial distribution on a 4000 watts CO2 c.w. laser source (Cilas CI 4000)

Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black‐carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom‐up inventory methods are 7500 Gg yr−1in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial‐era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m−2with 90% uncertainty bounds of (+0.08, +1.27) W m−2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m−2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial‐era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m−2with 90% uncertainty bounds of +0.17 to +2.1 W m−2. Thus, there is a very high probability that black carbon emissions, independent of co‐emitted species, have a positive forcing and warm the climate. We estimate that black carbon, with a total climate forcing of +1.1 W m−2, is the second most important human emission in terms of its climate forcing in the present‐day atmosphere; only carbon dioxide is estimated to have a greater forcing. Sources that emit black carbon also emit other short‐lived species that may either cool or warm climate. Climate forcings from co‐emitted species are estimated and used in the framework described herein. When the principal effects of short‐lived co‐emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy‐related sources (fossil fuel and biofuel) have an industrial‐era climate forcing of +0.22 (−0.50 to +1.08) W m−2during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all short‐lived emissions from these sources would reduce net climate forcing (i.e., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial‐era climate forcing by all short‐lived species from black‐carbon‐rich sources becomes slightly negative (−0.06 W m−2with 90% uncertainty bounds of −1.45 to +1.29 W m−2). The uncertainties in net climate forcing from black‐carbon‐rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co‐emitted organic carbon. In prioritizing potential black‐carbon mitigation actions, non‐science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near‐term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black‐carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.

Background: To investigate whether features of muscular complaints (MC) differ between receivers of a statin prescription and non-receivers. To analyze the relationship between analgesics prescription, statin prescription and/or musculoskeletal disorders. Methods: Cross-sectional study. Consecutive patients in offices of family practitioners were interviewed using a standardized questionnaire. Target variables: Rates of features of MC in patients with or without a statin prescription and rates of analgesic drug prescription in patients with or without statin prescription and/or musculoskeletal disorders. Odds ratios (adjusted for age, sex, and socio-economic status) were calculated using logistic regression analysis. Results: 1135 patients in 26 general practitioners’ offices were asked to participate, and 1031 patients agreed. Features of MC did not differ between the two groups of patients. Analgesic prescription was found to be associated with statin prescription in patients without musculoskeletal disorders (OR 2.2, CI 1.1-4.7 without statin, OR 2.5, CI 0.9-6.9 with statin) and particularly in those with musculoskeletal disorders (OR 5.2, CI 2.9-9.3 without statin, OR 9.3, CI 4.5-19.1 with statin). Conclusions: Analgesic prescriptions are probably positively associated with statin prescription. Assuming that analgesics attenuate MC, an even stronger association between MC and statin use seems likely. The results generate the hypothesis that statin use contributes to analgesic use in primary care patients.

Accurate fire emissions inventories are crucial to predict the impacts of wildland fires on air quality and atmospheric composition. Two traditional approaches are widely used to calculate fire emissions: a satellite‐based top‐down approach and a fuels‐based bottom‐up approach. However, these methods often considerably disagree on the amount of particulate mass emitted from fires. Previously available observational datasets tended to be sparse, and lacked the statistics needed to resolve these methodological discrepancies. Here, we leverage the extensive and comprehensive airborne in situ and remote sensing measurements of smoke plumes from the recent Fire Influence on Regional to Global Environments and Air Quality (FIREX‐AQ) campaign to statistically assess the skill of the two traditional approaches. We use detailed campaign observations to calculate and compare emission rates at an exceptionally high‐resolution using three separate approaches: top‐down, bottom‐up, and a novel approach based entirely on integrated airborne in situ measurements. We then compute the daily average of these high‐resolution estimates and compare with estimates from lower resolution, global top‐down and bottom‐up inventories. We uncover strong, linear relationships between all of the high‐resolution emission rate estimates in aggregate, however no single approach is capable of capturing the emission characteristics of every fire. Global inventory emission rate estimates exhibited weaker correlations with the high‐resolution approaches and displayed evidence of systematic bias. The disparity between the low‐resolution global inventories and the high‐resolution approaches is likely caused by high levels of uncertainty in essential variables used in bottom‐up inventories and imperfect assumptions in top‐down inventories. Smoke emitted by wildland fires is dangerous to human health and contributes to climate change. To predict and evaluate the impacts of fires, we need to know how much smoke is emitted into the atmosphere. There are two state‐of‐the‐art methods used to estimate the mass of smoke emitted by fires, but they often disagree. In this study, we use unusually detailed measurements collected using an aircraft that flew within wildland fire smoke plumes to calculate the amount of smoke emitted from fires in the Western United States. We compare emission rates derived from the exceptionally high spatial and temporal resolution approach to the two traditional, lower resolution approaches to understand why they sometimes diverge. In situ measurements of wildland fire smoke plumes provide emission rates for evaluating emissions inventories at unprecedented resolutionFire emissions inventories struggle to capture the emissions rate characteristics of individual fires but may perform well in the aggregateBottom‐up inventories suffer from major uncertainty in key variables, while top‐down inventories may have bias from imperfect assumptions In situ measurements of wildland fire smoke plumes provide emission rates for evaluating emissions inventories at unprecedented resolution Fire emissions inventories struggle to capture the emissions rate characteristics of individual fires but may perform well in the aggregate Bottom‐up inventories suffer from major uncertainty in key variables, while top‐down inventories may have bias from imperfect assumptions