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Wind energy is helping to decarbonize the electrical grid, but wind blades are not recyclable, and current end-of-life management strategies are not sustainable. To address the material recyclability challenges in sustainable energy infrastructure, we introduce scalable biomass-derivable polyester covalent adaptable networks and corresponding fiber-reinforced composites for recyclable wind blade fabrication. Through experimental and computational studies, including vacuum-assisted resin-transfer molding of a 9-meter wind blade prototype, we demonstrate drop-in technological readiness of this material with existing manufacture techniques, superior properties relative to incumbent materials, and practical end-of-life chemical recyclability. Most notable is the counterintuitive creep suppression, outperforming industry state-of-the-art thermosets despite the dynamic cross-link topology. Overall, this report details the many facets of wind blade manufacture, encompassing chemistry, engineering, safety, mechanical analyses, weathering, and chemical recyclability, enabling a realistic path toward biomass-derivable, recyclable wind blades.

Large composite structures, such as those used in wind energy applications, rely on the bulk polymerization of thermosets on an impressively large scale. To accomplish this, traditional thermoset polymerizations require both elevated temperatures (>100 °C) and extended cure durations (>5 h) for complete conversion, necessitating the use of oversize ovens or heated molds. In turn, these requirements lead to energy-intensive polymerizations, incurring high manufacturing costs and process emissions. In this study, we develop thermoset polymerizations that can be initiated at room temperature through a transformative "chemical heating" concept, in which the exothermic energy of a secondary reaction is used to facilitate the heating of a primary thermoset polymerization. By leveraging a redox-initiated methacrylate free radical polymerization as a source of exothermic chemical energy, we can achieve peak reaction temperatures >140 °C to initiate the polymerization of epoxy-anhydride thermosets without external heating. Furthermore, by employing Trojan horse methacrylate monomers to induce mixing between methacrylate and epoxy-anhydride domains, we achieve the synthesis of homogeneous hybrid polymeric materials with competitive thermomechanical properties and tunability. Herein, we establish a proof-of-concept for our innovative chemical heating method and advocate for its industrial integration for more energy-efficient and streamlined manufacturing of wind blades and large composite parts more broadly., Competing Interests: The authors declare the following competing financial interest(s): MLM, NAR, and RDA have submitted patent applications on recyclable-by-design materials and the DC strategy. All other authors declare no competing interests., (© 2024 The Authors. Published by American Chemical Society.)

Despite considerable recent advances already made in developing chemically circular polymers (CPs), the current framework predominantly focuses on CPs with linear-chain structures of different monomer types. As polymer properties are determined by not only composition but also topology, manipulating the topology of the single-monomer-based CP systems from linear-chain structures to architecturally complex polymers could potentially modulate the resulting polymer properties without changing the chemical composition, thereby advancing the concept of monomaterial product design. To that end, here, we introduce a chemically circular hyperbranched polyester (HBPE), synthesized by a mixed chain-growth and step-growth polymerization of a rationally designed bicyclic lactone with a pendent hydroxyl group (BiL OH ). This HBPE exhibits full chemical recyclability despite its architectural complexity, showing quantitative selectivity for regeneration of BiL OH , via a unique cascade depolymerization mechanism. Moreover, distinct differences in materials properties and performance arising from topological variations between HBPE, hb -PBiL OH , and its linear analogue, l -PBiL OH , have been revealed where generally the branched structure led to more favorable interchain interactions, and topology-amplified optical activity has also been observed for chiral (1 S , 4 S , 5 S )- hb -PBiL OH . More intriguingly, depolymerization of l -PBiL OH proceeds through an unexpected, initial topological transformation to the HBPE polymer, followed by the faster cascade depolymerization pathway adopted by hb -PBiL OH . Overall, these results demonstrate that CP design can go beyond typical linear polymers, and rationally redesigned, architecturally complex polymers for their unique properties may synergistically impart advantages in topology-augmented depolymerization acceleration and selectivity for exclusive monomer regeneration.

Cyclic block copolymers ( c BCP) are fundamentally intriguing materials, but their synthetic challenges that demand precision in controlling both the monomer sequence and polymer topology limit access to AB and ABC block architectures. Here, we show that cyclic ABAB tetra-BCPs ( c ABAB) and their linear counterpart ( l ABAB) can be readily obtained at a speed and scale from one-pot (meth)acrylic monomer mixtures, through coupling the Lewis pair polymerization's unique compounded-sequence control with its precision in topology control. This approach achieves fast (<15 min) and quantitative (>99%) conversion to tetra-BCPs of predesignated linear or cyclic topology at scale (40 g) in a one-pot procedure, precluding the needs for repeated chain extensions, stoichiometric addition steps, dilute conditions, and postsynthetic modifications, and/or postsynthetic ring-closure steps. The resulting l ABAB and c ABAB have essentially identical molecular weights ( M n = 165-168 kg mol -1 ) and block degrees/symmetry, allowing for direct behavioral comparisons in solution (hydrodynamic volume, intrinsic viscosity, elution time, and refractive indices), bulk (thermal transitions), and film (thermomechanical and rheometric properties and X-ray scattering patterns) states. To further the morphological characterizations, allylic side-chain functionality is exploited via the thiol-ene click chemistry to install crystalline octadecane side chains and promote phase separation between the A and B blocks, allowing visualization of microdomain formation.

Successes in biocatalytic polyester recycling have raised the possibility of deconstructing alternative polymers enzymatically, with polyamide (PA) being a logical target due to the array of amide-cleaving enzymes present in nature. Here, we screen 40 potential natural and engineered nylon-hydrolyzing enzymes (nylonases), using mass spectrometry to quantify eight compounds resulting from enzymatic nylon-6 (PA6) hydrolysis. Comparative time-course reactions incubated at 40-70 °C showcase enzyme-dependent variations in product distributions and extent of PA6 film depolymerization, with significant nylon deconstruction activity appearing rare. The most active nylonase, a NylC K variant we rationally thermostabilized (an N-terminal nucleophile (Ntn) hydrolase, NylC K -TS, T m  = 87.4 °C, 16.4 °C higher than the wild-type), hydrolyzes 0.67 wt% of a PA6 film. Reactions fail to restart after fresh enzyme addition, indicating that substrate-based limitations, such as restricted enzyme access to hydrolysable bonds, prohibit more extensive deconstruction. Overall, this study expands our understanding of nylonase activity distribution, indicates that Ntn hydrolases may have the greatest potential for further development, and identifies key targets for progressing PA6 enzymatic depolymerization, including improving enzyme activity, product selectivity, and enhancing polymer accessibility., (© 2024. The Author(s).)

Cross-linked elastomers are stretchable materials that typically are not recyclable or biodegradable. Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) are soft and ductile, making these bio-based polymers good candidates for biodegradable elastomers. Elasticity is commonly imparted by a cross-linked network structure, and covalent adaptable networks have emerged as a solution to prepare recyclable thermosets via triggered rearrangement of dynamic covalent bonds. Here, we develop biodegradable and recyclable elastomers by chemically installing the covalent adaptable network within biologically produced mcl-PHAs. Specifically, an engineered strain of Pseudomonas putida was used to produce mcl-PHAs containing pendent terminal alkenes as chemical handles for postfunctionalization. Thiol-ene chemistry was used to incorporate boronic ester (BE) cross-links, resulting in PHA-based vitrimers. mcl-PHAs cross-linked with BE at low density (<6 mole %) affords a soft, elastomeric material that demonstrates thermal reprocessability, biodegradability, and denetworking at end of life. The mechanical properties show potential for applications including adhesives and soft, biodegradable robotics and electronics.

Optogenetic actuators have revolutionized the resolution at which biological processes can be controlled. In plants, deployment of optogenetics is challenging due to the need for these light-responsive systems to function in the context of horticultural light environments. Furthermore, many available optogenetic actuators are based on plant photoreceptors that might crosstalk with endogenous signaling processes, while others depend on exogenously supplied cofactors. To overcome such challenges, we have developed Highlighter, a synthetic, light-gated gene expression system tailored for in planta function. Highlighter is based on the photoswitchable CcaS-CcaR system from cyanobacteria and is repurposed for plants as a fully genetically encoded system. Analysis of a re-engineered CcaS in Escherichia coli demonstrated green/red photoswitching with phytochromobilin, a chromophore endogenous to plants, but also revealed a blue light response likely derived from a flavin-binding LOV-like domain. We deployed Highlighter in transiently transformed Nicotiana benthamiana for optogenetic control of fluorescent protein expression. Using light to guide differential fluorescent protein expression in nuclei of neighboring cells, we demonstrate unprecedented spatiotemporal control of target gene expression. We implemented the system to demonstrate optogenetic control over plant immunity and pigment production through modulation of the spectral composition of broadband visible (white) light. Highlighter is a step forward for optogenetics in plants and a technology for high-resolution gene induction that will advance fundamental plant biology and provide new opportunities for crop improvement., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Larsen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Chemically recyclable, circular polymers continue to attract increasing attention, but rendering both catalysts for depolymerization and high-performance polymers recyclable is a more sustainable yet challenging goal. Here we introduce a dual catalyst/polymer recycling system in that recyclable inorganic phosphomolybdic acid catalyzes selective depolymerization of high-ceiling-temperature biodegradable poly(δ-valerolactone) in bulk phase, which, upon reaching suitable molecular weight, exhibits outstanding mechanical performance with a high tensile strength of ≈66.6 MPa, fracture strain of ≈904 %, and toughness of ≈308 MJ m -3 , and thus markedly outperforms commodity polyolefins, recovering its monomer in pure state and quantitative yield at only 100 °C. In sharp contrast, the uncatalyzed depolymerization not only requires a high temperature of >310 °C but is also low yielding and non-selective. Importantly, the recovered monomer can be repolymerized as is to reproduce the same polymer, thereby closing the circular loop, and the recycled catalyst can be reused repeatedly for depolymerization runs without loss of its catalytic activity and efficiency., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The global plastics problem is a trifecta, greatly affecting environment, energy and climate 1-4 . Many innovative closed/open-loop plastics recycling or upcycling strategies have been proposed or developed 5-16 , addressing various aspects of the issues underpinning the achievement of a circular economy 17-19 . In this context, reusing mixed-plastics waste presents a particular challenge with no current effective closed-loop solution 20 . This is because such mixed plastics, especially polar/apolar polymer mixtures, are typically incompatible and phase separate, leading to materials with substantially inferior properties. To address this key barrier, here we introduce a new compatibilization strategy that installs dynamic crosslinkers into several classes of binary, ternary and postconsumer immiscible polymer mixtures in situ. Our combined experimental and modelling studies show that specifically designed classes of dynamic crosslinker can reactivate mixed-plastics chains, represented here by apolar polyolefins and polar polyesters, by compatibilizing them via dynamic formation of graft multiblock copolymers. The resulting in-situ-generated dynamic thermosets exhibit intrinsic reprocessability and enhanced tensile strength and creep resistance relative to virgin plastics. This approach avoids the need for de/reconstruction and thus potentially provides an alternative, facile route towards the recovery of the endowed energy and materials value of individual plastics., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: We based this study on the sexual wholeness model, which considers emotional, physical, and meaning elements of sexuality, and previous research that indicates variability in the associations among orgasm consistency, relational satisfaction, and sexual satisfaction., Aim: We performed a person-based latent class approach to examine variables linked with the trifecta of orgasm consistency, relational satisfaction, and sexual satisfaction., Methods: We used a Mechanical Turk sample that consisted of 1645 sexually active participants (1032 women) to evaluate classes and related variables., Outcomes: Women divided into 5 classes and men into 3 classes. High orgasm consistency alone did not ensure sexual or relational satisfaction., Results: We found that 5 groups emerged for women: high orgasm/low satisfaction (6%), low trifecta (8%), low orgasm/high satisfaction (16%), moderate orgasm/high satisfaction (15%), and high trifecta (55%). For men, 3 groups emerged: lower orgasm/high satisfaction (12%), moderate trifecta (14%), and high trifecta (74%). We also found that high orgasm consistency for women did not guarantee relational and sexual satisfaction, nor did lower orgasm consistency for men or women guarantee problematic relational and sexual satisfaction., Clinical Implications: Communication, attachment, and sexual harmony were key elements associated with positive trifecta outcomes. Clinicians and educators may emphasize the importance of these variables when individuals encounter sexual or relational distress., Strengths and Limitations: Data analytic techniques revealed a variety of groups for men and women and associations between a host of physical, psychological, and meaning variables and the trifecta of orgasm consistency, relational satisfaction, and sexual satisfaction. However, this study is cross-sectional and correlational, which limits the conclusions that we can draw from it., Conclusion: While the variables of orgasm consistency, relational satisfaction, and sexual satisfaction are each informative, together they help clinicians, educators, and researchers better understand the complexity of sex., (© The Author(s) 2023. Published by Oxford University Press on behalf of The International Society of Sexual Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Geminal disubstitution of cyclic monomers is an effective strategy to enhance the chemical recyclability of their polymers, but it is utilized for that purpose alone and often at the expense of performance properties. Here we present synergistic use of gem-α,α-disubstitution of available at-scale, bio-based δ-valerolactones to yield gem-dialkyl-substituted valerolactones ([Formula: see text]), which generate polymers that solve not only the poor chemical recyclability but also the low melting temperature and mechanical performance of the parent poly(δ-valerolactone); the gem-disubstituted polyesters ([Formula: see text]) therefore not only exhibit complete chemical recyclability but also thermal, mechanical and transport properties that rival or exceed those of polyethylene. Through a fundamental structure-property study that reveals intriguing impacts of the alkyl chain length on materials performance of [Formula: see text], this work establishes a simple circular, high-performance polyester platform based on [Formula: see text] and highlights the importance of synergistic utilization of gem-disubstitution for enhancing both chemical recyclability and materials performance of sustainable polyesters., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

There are a variety of conditions under which religiosity may be positively or negatively associated with sexual and relationship satisfaction. To better understand these conditions, we conducted two studies using two separate samples: one with individuals (1,695 individuals), and one with couples (481 dyads), to test how sexual sanctification and sexual mindfulness moderate these associations. Across studies sexual mindfulness was positively associated with sexual and relationship satisfaction for the individual and partner, but there was no evidence for moderation; sexual sanctification was consistently associated with higher sexual and relationship satisfaction, and in some cases moderated the association between religiosity and both sexual and relationship satisfaction for women and men. In Study 1, religiosity was associated with lower sexual and relationship satisfaction for both men and women when sexual sanctification was low, but not with either type of satisfaction when sexual sanctification was high. In Study 2, religiosity was positively associated with sexual satisfaction for men but only when sexual sanctification was high. The combined evidence indicates that sexual sanctification may be one factor that distinguishes whether religion helps or hinders sexual and relationship satisfaction.

The design of facile synthetic routes to well-defined block copolymers (BCPs) from direct polymerization of one-pot comonomer mixtures, rather than traditional sequential additions, is both fundamentally and technologically important. Such synthetic methodologies often leverage relative monomer reactivity toward propagating species exclusively and therefore are rather limited in monomer scope and control over copolymer structure. The recently developed compounded sequence control (CSC) by Lewis pair polymerization (LPP) utilizes synergistically both thermodynamic ( K eq ) and kinetic ( k p ) differentiation to precisely control BCP sequences and suppress tapering and misincorporation errors. Here, we present an in-depth study of CSC by LPP, focusing on the complex interplay of the fundamental K eq and k p parameters, which enable the unique ability of CSC-LPP to precisely control comonomer sequences across a variety of polar vinyl monomer classes. Individual Lewis acid equilibrium and polymerization rate parameters of a range of commercially relevant monomers were experimentally quantified, computationally validated, and rationalized. These values allowed for the judicious design of copolymerizations which probed multiple hypotheses regarding the constructive vs conflicting nature of the relationship between K eq and k p biases, which arise during CSC-LPP of comonomer mixtures. These relationships were thoroughly explored and directly correlated with resultant copolymer microstructures. Several examples of higher-order BCPs are presented, further demonstrating the potential for materials innovation offered by this methodology.

In typical cyclic polymer synthesis via ring-closure, chain growth and cyclization events are competing with each other, thus affording cyclic polymers with uncontrolled molecular weight or ring size and high dispersity. Here we uncover a mechanism by which Lewis pair polymerization (LPP) operates on polar vinyl monomers that allows the control of where and when cyclization takes place, thereby achieving spatial and temporal control to afford precision cyclic vinyl polymers or block copolymers with predictable molecular weight and low dispersity (≈1.03). A combined experimental and theoretical study demonstrates that cyclization occurs only after all monomers have been consumed (when) via conjugate addition of the propagating chain end to the specific site of the initiating chain end (where), allowing the cyclic polymer formation steps to be regulated and executed with precision in space and time., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Two well-known low-ceiling-temperature (LCT) monomers, γ-butyrolactone (γ-BL) toward ring-opening polymerization (ROP) to polyester and cyclohexene toward ring-opening metathesis polymerization (ROMP) to poly(cyclic olefin), are notoriously "nonpolymerizable". Here we present a strategy to render not only polymerizability of both the γ-BL and cyclohexene sites, orthogonally, but also complete and orthogonal depolymerization, through creating an LCT/LCT hybrid, bicyclic lactone/olefin (BiL = ). This hybrid monomer undergoes orthogonal polymerization between ROP and ROMP, depending on the catalyst employed, affording two totally different classes of polymeric materials from this single monomer: polyester P(BiL = ) ROP via ROP and functionalized poly(cyclic olefin) P(BiL = ) ROMP via ROMP. Intriguingly, both P(BiL = ) ROP and P(BiL = ) ROMP are thermally robust but chemically recyclable under mild conditions (25-40 °C), in the presence of a catalyst, to recover cleanly the same monomer via chain unzipping and scission, respectively. In the ROP, topological and stereochemical controls have been achieved and the structures characterized. Furthermore, the intact functional group during the orthogonal polymerization (i.e., the double bond in ROP and the lactone in ROMP) is utilized for postfunctionalization for tuning materials' thermal and mechanical performances. The impressive depolymerization orthogonality further endows selective depolymerization of both the ROP/ROMP copolymer and the physical blend composites into the same starting monomer.

The association between religiosity and the construct of sexual passion was examined to see whether religiosity is associated with harmonious, inhibited, and obsessive sexual passion styles. Using multiple regression and checking for interactions between religiosity, gender, broad categories of religion (Catholic, other Christian, other religious, nonreligious), and the three sexual passion styles, the following associations were found: Religiosity had a significant curvilinear relationship to all three sexual passion styles, suggesting an overlap in levels of religiosity and the construct of sexual passion. Optimal sexual passion outcomes were found at both higher and lower levels of religiosity, whereas mid-level religiosity was associated with the less beneficial sexual passion outcomes. Religious men were significantly more obsessively passionate than religious women, and religious men and women were similarly high on levels of harmonious and low on inhibited sexual passion. There were no significant interactions between religiosity, broad categories of religion, and sexual passion styles. Understanding how religion and sexual passion are associated could be useful for applied researchers as well as those who work with religious individuals who want to help these individuals develop beneficial patterns of sexual passion.

Marriage is an important adult relationship, and recent research indicates that sexual mindfulness, awareness and non-judgment, may be an important tool in helping maintain relational and sexual well-being. Using a nationally representative U.S. sample of newly married, mixed-sex couples (women's age M = 29.70 years; men's age M = 31.76 years; N = 1473 couples), we evaluated whether the two factors of sexual mindfulness, awareness and non-judgment, were linked with relational flourishing, sexual harmony, and orgasm consistency. We utilized an actor-partner interdependence model within a structural equation modeling framework to evaluate how husbands' and wives' awareness and non-judgment were associated with relational flourishing, sexual harmony, and orgasm consistency. Results indicated that both wives' and husbands' awareness was positively associated with relational flourishing, sexual harmony, and orgasm consistency. Partner effects were found for all outcomes. However, no partner effects were found between non-judgment and orgasm consistency. Therapists, educators, and couples may consider the use of sexual mindfulness skills when addressing marriage and sexual relationships., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

We investigated the intersection of religion and boundaries placed around sex using qualitative data from 198 highly religious Muslim, Christian, and Jewish families. Coding performed by two researchers resulted in six core themes that provide insight into the connection between these two domains. Frequency counts of the core themes, participant quotes, and implications are presented-including the benefits of practitioners inquiring into how clients' faith affects sexual behavior and scripts, how fidelity and vows might serve a protective function for the relationships of highly religious couples, and how religion may empower women in terms of sexual boundary setting.

Precision synthesis of cyclic polymers with predictable molecular weight and low dispersity is a challenging task, particularly concerning cyclic polar vinyl polymers through a rapid chain-growth mechanism and without high dilution. Harder yet is the precision synthesis of cyclic block copolymers ( c BCPs), ideally from comonomer mixtures. Here we report that Lewis pair polymerization (LPP) capable of thermodynamically and kinetically compounded sequence control successfully addressed this longstanding challenge. Thus, LPP of acrylate/methacrylate mixtures under ambient temperature and normal concentration conditions rapidly and selectively affords well-defined c BCPs with high molecular weight ( M n = 247 kg/mol) and low dispersity ( Đ = 1.04) in one step. Such c BCPs have been characterized by multiple techniques, including direct structural observation by imaging.

There are three regimes of cell membrane interaction with glass: Tight and loose adhesion, separated by repulsion. Explicitly including hydration, this paper evaluates the pressure between the surfaces as functions of distance for ion correlation and ion-screened electrostatics and electromagnetic fluctuations. The results agree with data for tight adhesion energy (0.5-3 vs 0.4-4 mJ/m^{2}), detachment pressure (7.9 vs. 9 MPa), and peak repulsion (3.4-7.5 vs. 5-10 kPa), also matching the repulsion's distance dependence on renormalization by steric pressure mainly from undulations.

Background: Curvilinearity has been found for sexual frequency, but research has not examined whether curvilinear associations exist for other aspects of sexual relationships like orgasm consistency., Aim: We examined whether there is curvilinearity and the nature of that curvilinearity between orgasm consistency and sexual and relational satisfaction for men and women., Methods: With pooled samples of 1,619 and 1,695 men and women from Amazon's Mechanical Turk, we examined the differences of orgasm consistency values and both sexual satisfaction and relationship satisfaction through analysis of variance. We then tested for curvilinearity between orgasm consistency and sexual and relational satisfaction with regression analyses., Outcomes: For men we found no evidence of a curvilinear relationship, but for women we found a curvilinear relationship between orgasm consistency values and both sexual satisfaction and relationship satisfaction., Results: Across tests, the overall picture suggests that there is no curvilinear association for men, but there is for women. For women, with each unit increase in orgasm consistency, the increase in sexual satisfaction and relationship satisfaction became progressively smaller. Past the 61-80% threshold for orgasm consistency, there was little gain in sexual satisfaction and no gain in relational satisfaction., Clinical Translation: Physicians, therapists, and educators can reorient women's orgasm expectations by explaining that having regular orgasms-not necessarily always-is associated with satisfaction in their relationship and sexual experience., Strengths & Limitations: Converging large samples and data analytic techniques evinced the curvilinear association between orgasm consistency and both relational and sexual satisfaction for women. However, this study is cross-sectional and correlational, which limits the conclusions we can draw from it., Conclusion: While men's orgasm consistency is linearly associated with relational and sexual satisfaction, more consistent orgasms seem to be associated with women's sexual and relational satisfaction, to a point. Leavitt CE, Leonhardt ND, Busby DM, et al. When Is Enough Enough? Orgasm's Curvilinear Association With Relational and Sexual Satisfaction. J Sex Med 2021;18:167-178., (Copyright © 2020 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.)

The ability to synthesize well-defined block copolymers (BCPs) from one-pot comonomer mixtures has powerful chemical and practical implications. However, controlling sequences between highly reactive, homologous comonomers such as acrylates during polymerization is challenging. Here we present a Lewis pair polymerization strategy that uniquely utilizes preferential Lewis acid coordination to differentiate between comonomers, distinctive kinetics, and compounded thermodynamic and kinetic differentiation to precisely control sequences and suppress tapering and misincorporation errors, thus achieving well-defined and resolved di- or tri-BCPs of acrylates.

Tobacco smoke-induced lung inflammation in patients with chronic obstructive pulmonary disease (COPD) worsens with disease progression and acute exacerbations caused by respiratory infections. Chronic therapies to manage COPD center on bronchodilators to improve lung function and inhaled corticosteroids (ICS) to help reduce the risk of exacerbations. Novel therapies are needed that reduce the underlying inflammation associated with COPD and the inflammation resulting from respiratory infections that worsen disease. The lung is lined with airway surface liquid (ASL), a rheologically active material that provides an innate defense for the airway against inhaled particulate and is continuously cleared from the airways by mucociliary clearance. The rheological properties of the ASL can be altered by changes in airway hydration and by cations, such as calcium, that interact with electronegative glycoproteins. The effect of inhaled salts on inflammation resulting from tobacco smoke exposure was studied to determine if cations could be used to alter the properties of the ASL and reduce inflammation. Inhaled calcium salts, but not sodium or magnesium salts, reduced cellular inflammation and key chemokines and cytokines that were induced by tobacco smoke exposure. Similar anti-inflammatory effects of calcium salts were observed using in vitro cultures of human monocyte derived macrophages and human bronchial epithelial cells. The data suggest that inhaled calcium salts may act broadly on both biophysical and biological pathways to reduce pulmonary inflammation., (Copyright © 2018. Published by Elsevier Ltd.)

Directly examining subcellular mechanics whilst avoiding excessive strain of a live cell requires the precise control of light stress on very small areas, which is fundamentally difficult. Here we use a glass nanopipet out of contact with the plasma membrane to both exert the stress on the cell and also accurately monitor cellular compression. This allows the mapping of cell stiffness at a lateral resolution finer than 100 nm. We calculate the stress a nanopipet exerts on a cell as the sum of the intrinsic pressure between the tip face and the plasma membrane plus its direct pressure on any glycocalyx, both evaluated from the gap size in terms of the ion current decrease. A survey of cell types confirms that an intracellular pressure of approximately 120 Pa begins to detach the plasma membrane from the cytoskeleton and reveals that the first 0.66 ± 0.09 μm of compression of a neuron cell body is much softer than previous methods have been able to detect.

Background: Acute mastoiditis is a significant cause of morbidity in the paediatric population. This paper reviews our experience with this condition over the last 10 years and compares it with historical data from Alder Hey Children's Hospital, Liverpool, UK., Method: A retrospective case note review of patients who presented between 2003 and 2012 was performed., Results: Forty-six patients with acute mastoiditis were identified. Imaging with computed tomography and magnetic resonance imaging was carried out in 14 cases (30.4 per cent). Intracranial complications were identified in six patients (13.0 per cent), one of whom required neurosurgical intervention. In 27 cases (58.7 per cent), a surgical procedure was performed. Data from 1995 to 2000 revealed similar rates of imaging (30.0 per cent), but significantly lower rates of surgical intervention (23 per cent). A lower rate of intracranial complications (4.8 per cent) in the historical cohort did not prove to be statistically significant (p = 0.419)., Conclusion: The numbers of paediatric patients presenting with acute mastoiditis appears essentially unchanged. Improvement in imaging technology and aids to interpretation may explain the apparent increase of intracranial complications.

This paper discusses physical and structural aspects of the mechanisms herpes simplex virus (HSV) uses for membrane fusion. Calculations show that herpes simplex virus glycoprotein D has such avidity for its receptors that it can hold the virion against the plasma membrane of a neuron strongly enough for glycoprotein B (gB) to disrupt both leaflets of the bilayer. The strong electric field generated by the cell potential across perforations at this disruption would break the hydrogen bonds securing the gB fusion loops, leading to fusion of the plasma and viral membranes. This mechanism agrees with the high stability of the tall trimeric spike structure of gB and is consistent with the probable existence of a more compact initial conformation that would allow it to closely approach the plasma membrane. The release of the fusion domains by disruption of hydrogen bonds is shared with the endocytotic entry pathway where, for some cell types not punctured by gB, the virus is able to induce inward forces that cause endocytosis and the fusion loops are released by acidification. The puncture-fusion mechanism requires low critical strain or high tissue strain, matching primary tropism of neural processes at the vermillion border. In support of this mechanism, this paper proposes a functional superstructure of the antigens essential to entry and reviews its consistency with experimental evidence.

Herpes simplex viruses display hundreds of gD glycoproteins, and yet their neutralization requires tens of thousands of antibodies per virion, leading us to ask whether a wild-type virion with just a single free gD is still infective. By quantitative analysis of fluorescently labeled virus particles and virus neutralization assays, we show that entry of a wild-type HSV virion to a cell does indeed require just one or two of the approximately 300 gD glycoproteins to be left unbound by monoclonal antibody. This indicates that HSV entry is an extraordinarily efficient process, functioning at the level of single molecular complexes.

There is an intrinsic repulsion between glass and cell surfaces that allows noninvasive scanning ion conductance microscopy (SICM) of cells and which must be overcome in order to form the gigaseals used for patch clamping investigations of ion channels. However, the interactions of surfaces in physiological solutions of electrolytes, including the presence of this repulsion, for example, do not obviously agree with the standard Derjaguin-Landau-Verwey-Overbeek (DLVO) colloid theory accurate at much lower salt concentrations. In this paper we investigate the interactions of glass nanopipettes in this high-salt regime with a variety of surfaces and propose a way to resolve DLVO theory with the results. We demonstrate the utility of this understanding to SICM by topographically mapping a live cell's cytoskeleton. We also report an interesting effect whereby the ion current though a nanopipette can increase under certain conditions upon approaching an insulating surface, rather than decreasing as would be expected. We propose that this is due to electroosmotic flow separation, a high-salt electrokinetic effect. Overall these experiments yield key insights into the fundamental interactions that take place between surfaces in strong solutions of electrolytes.

In this work we show how hydrodynamic forces can be used to locally trap molecules in a supported lipid bilayer (SLB). The method uses the hydrodynamic drag forces arising from a flow through a conical pipette with a tip radius of 1-1.5 μm, placed approximately 1 μm above the investigated SLB. This results in a localized forcefield that acts on molecules protruding from the SLB, yielding a hydrodynamic trap with a size approximately given by the size of the pipette tip. We demonstrate this concept by trapping the protein streptavidin, bound to biotin receptors in the SLB. It is also shown how static and kinetic information about the intermolecular interactions in the lipid bilayer can be obtained by relating how the magnitude of the hydrodynamic forces affects the accumulation of protein molecules in the trap.

Here, we use single-molecule techniques to study the aggregation of α-synuclein, the protein whose misfolding and deposition is associated with Parkinson's disease. We identify a conformational change from the initially formed oligomers to stable, more compact proteinase-K-resistant oligomers as the key step that leads ultimately to fibril formation. The oligomers formed as a result of the structural conversion generate much higher levels of oxidative stress in rat primary neurons than do the oligomers formed initially, showing that they are more damaging to cells. The structural conversion is remarkably slow, indicating a high kinetic barrier for the conversion and suggesting that there is a significant period of time for the cellular protective machinery to operate and potentially for therapeutic intervention, prior to the onset of cellular damage. In the absence of added soluble protein, the assembly process is reversed and fibrils disaggregate to form stable oligomers, hence acting as a source of cytotoxic species., (Copyright © 2012 Elsevier Inc. All rights reserved.)

We have experimentally determined the optimal flow velocities to characterize or count single molecules by using a simple microfluidic device to perform two-color coincidence detection (TCCD) and single pair Förster resonance energy transfer (spFRET) using confocal fluorescence spectroscopy on molecules traveling at speeds of up to 10 cm s(-1). We show that flowing single fluorophores at ≥0.5 cm s(-1) reduces the photophysical processes competing with fluorescence, enabling the use of high excitation irradiances to partially compensate for the short residence time within the confocal volume (10-200 μs). Under these conditions, the data acquisition rate can be increased by a maximum of 38-fold using TCCD at 5 cm s(-1) or 18-fold using spFRET at 2 cm s(-1), when compared with diffusion. While structural characterization requires more photons to be collected per event and so necessitates the use of slower speeds (2 cm s(-1) for TCCD and 1 cm s(-1) for spFRET), a considerable enhancement in the event rate could still be obtained (33-fold for TCCD and 16-fold for spFRET). Using flow under optimized conditions, analytes could be rapidly quantified over a dynamic range of up to 4 orders of magnitude by direct molecule counting; a 50 fM dual-labeled model sample can be detected with 99.5% statistical confidence in around 8 s using TCCD and a flow velocity of 5 cm s(-1)., (© 2011 American Chemical Society)

In recent genome-wide association studies, the extracellular chaperone protein, clusterin, has been identified as a newly-discovered risk factor in Alzheimer's disease. We have examined the interactions between human clusterin and the Alzheimer's disease-associated amyloid-β(1-40) peptide (Aβ(1-40)), which is prone to aggregate into an ensemble of oligomeric intermediates implicated in both the proliferation of amyloid fibrils and in neuronal toxicity. Using highly sensitive single-molecule fluorescence methods, we have found that Aβ(1-40) forms a heterogeneous distribution of small oligomers (from dimers to 50-mers), all of which interact with clusterin to form long-lived, stable complexes. Consequently, clusterin is able to influence both the aggregation and disaggregation of Aβ(1-40) by sequestration of the Aβ oligomers. These results not only elucidate the protective role of clusterin but also provide a molecular basis for the genetic link between clusterin and Alzheimer's disease.

Background: Matrix metalloproteinase (MMP) 9 is a gelatinase associated with tissue remodeling. It is thought to play a part in the pathogenesis of allergy. Increased levels of MMP-9 have been shown to increase in the acute allergic response in the nose, lungs, and skin. Exposure to passive tobacco smoke is associated with an increase in sneezing, nasal blockage, and a decreased sense of smell. The aim of this study was to study the effect of passive smoking on the levels of MMP-9 in nasal secretions of children., Methods: A prospective descriptive study was performed. Thirty-nine children aged between 7 and 16 years were enrolled in the study. They were selected based on attendance at the Otorhinolaryngology Outpatients Clinic with a primary complaint unrelated to the nose or paranasal sinuses. Children with allergic rhinitis, sinusitis, or a recent cold were excluded. The study was performed at a tertiary pediatric referral center. Exposure to passive smoking was determined by measuring the urinary cotinine to creatinine ratio. Nasal fluid was obtained by using a Rhino-Probe curette (Arlington Scientific, Inc., Springville, UT). The concentration of MMP-9 was determined by ELISA. MMP-9 activity was determined by gelatin zymography. Data were tabulated on Microsoft Excel (Microsoft Corp., Redmond, WA) and analyzed using SPSS (SPSS Inc., Chicago, IL)., Results: Using a cutoff urinary cotinine/creatinine ratio of 0.025 ng/mg, 15 children were found to be exposed to passive smoking. Both the MMP-9 concentration and the activity were significantly higher in nasal secretions of children exposed to passive smoking. There was a distinct difference between the two cohorts with regard to the level of enzyme activity per weight of protein. The lowest level of enzyme activity recorded in the "exposed" cohort was over twice that of the level in the "not exposed" cohort., Conclusion: MMP-9 activity and concentration is higher in nasal secretions of children exposed to passive smoking. This suggests that passive smoking might alter the inflammatory response within the nasal mucosa in a similar way to allergy.

The use of Förster resonance energy transfer (FRET) as a tool to study biomolecules has been greatly enhanced by new advances in single-molecule fluorescence (SMF) techniques. This has allowed new insights into the structure and dynamics of complex biomolecular machinery. However, there are still technical drawbacks in the application of conventional SMF-FRET. Herein, we review the use of single-molecule coincidence spectroscopy to study FRET systems, an analytical variation of the conventional scheme, using one or two confocal lasers of different colours. We highlight the advantages of the coincidence spectroscopy and illustrate this with examples of its application to some biological systems of interest., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: To assess the rate of tracheocutaneous fistula requiring surgical repair and the complications and outcomes following it in the ENT department of a tertiary referral university paediatric hospital., Methods: A retrospective review of all children requiring airway support with a tracheostomy between 1995 and 2009 and subsequently requiring closure of tracheocutaneous fistula., Results: One hundred and ninety-three children underwent 196 tracheostomies. Seventy-three children were successfully decannulated until now. Twenty-three children (11.9%) required subsequent surgical closure of their tracheocutaneous fistula. In all these children the age at tracheostomy was less than 1 year old, and the median age at decannulation was 4 years old, (range 2-9 yo). Surgical repair was undertaken 6-12 months after decannulation. There were 4 minor complications in the postoperative period (wound infection, haemorrhage and early recurrence) and no major complications. None of the patients have experienced any degree of significant airway stenosis and there was no need for a repeat tracheotomy in any of the tracheocutaneous fistula closure patients. The cosmetic results were deemed to be good., Conclusions: Our rate of tracheocutaneous fistula compares well with the reported rates in the literature (13-43%). There appears to be a significant relation to age at tracheostomy and duration of tracheostomy., (Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.)

Single-molecule fluorescence resonance energy transfer (FRET) is commonly used to probe different conformations and conformational dynamics of single biomolecules. However, the analysis of raw burst traces is not always straightforward. The presence of a "zero peak" and the skewness of peaks at high and low FRET efficiencies in proximity ratio histograms make the accurate evaluation of the histogram a challenging task. This is further compounded by the difficulty associated with siting two fluorophores in optimal range of each other. Here we present an alternative method of analysis, based on handling coincident FRET photon bursts, that addresses these problems. In addition, we demonstrate methods to enhance coincidence levels and thus the accuracy of FRET determination: the use of dual-color excitation, including direct excitation of the acceptor fluorophore; the addition of a remote dye to the biomolecule, not involved in the FRET process; or a combination of the two. We show the advantages of dual excitation by studying several labeled double-stranded DNA samples as FRET models. This method extends the application of single-molecule FRET to more complicated biological systems where only a small fraction of complexes are fully assembled.

A key issue in understanding the pathogenic conditions associated with the aberrant aggregation of misfolded proteins is the identification and characterization of species formed during the aggregation process. Probing the nature of such species has, however, proved to be extremely challenging to conventional techniques because of their transient and heterogeneous character. We describe here the application of a two-color single-molecule fluorescence technique to examine the assembly of oligomeric species formed during the aggregation of the SH3 domain of PI3 kinase. The single-molecule experiments show that the species formed at the stage of the reaction where aggregates have previously been found to be maximally cytotoxic are a heterogeneous ensemble of oligomers with a median size of 38 +/- 10 molecules. This number is remarkably similar to estimates from bulk measurements of the critical size of species observed to seed ordered fibril formation and of the most infective form of prion particles. Moreover, although the size distribution of the SH3 oligomers remains virtually constant as the time of aggregation increases, their stability increases substantially. These findings together provide direct evidence for a general mechanism of amyloid aggregation in which the stable cross-beta structure emerges via internal reorganization of disordered oligomers formed during the lag phase of the self-assembly reaction.