The flatwormMacrostomum lignanofeatures a duo-gland adhesive system that allows it to repeatedly attach to and release from substrates in seawater within a minute. However, little is known about the molecules involved in this temporary adhesion. In this study, we show that the attachment ofM. lignanorelies on the secretion of two large adhesive proteins,M. lignanoadhesion protein 1 (Mlig-ap1) and Mlig-ap2. We revealed that both proteins are expressed in the adhesive gland cells and that their distribution within the adhesive footprints was spatially restricted. RNA interference knockdown experiments demonstrated the essential function of these two proteins in flatworm adhesion. Negatively charged modified sugars in the surrounding water inhibited flatworm attachment, while positively charged molecules impeded detachment. In addition, we found thatM. lignanocould not adhere to strongly hydrated surfaces. We propose an attachment–release model where Mlig-ap2 attaches to the substrate and Mlig-ap1 exhibits a cohesive function. A small negatively charged molecule is secreted that interferes with Mlig-ap1, inducing detachment. These findings are of relevance for fundamental adhesion science and efforts to mitigate biofouling. Further, this model of flatworm temporary adhesion may serve as the starting point for the development of synthetic reversible adhesion systems for medicinal and industrial applications.

In the past many mechanisms of action have been proposed to explain the surfactant‐induced uptake of agrochemicals applied to foliage. These are reviewed briefly and discussed in relation to potential sites of uptake activation, particularly in the light of recent radiochemical work on the foliar uptake behaviour of surfactants on intact plants in the presence or absence of model penetrants and pesticides. The body of evidence available is examined in relation to the many outstanding problems that still exist in understanding the role and use of surfactants as uptake activators in agrochemical formulations.

The development of sodium ion batteries is largely motivated by the growing cost and limited resources of lithium. Titanium dioxide (TiO 2 ), in the form of selforganized and well-oriented nanotube arrays, are considered as a highly attractive anode material for sodium ion batteries, due to their inherent safety, low cost, and structural stability. This work reports on the sodiation and desodiation characteristics of anodically grown, self-organized TiO 2 nanotubes annealed in an Ar/C 2 H 2 atmosphere (TiO 2−x − C). It is found that anatase TiO 2−x −C nanotubes demonstrate substantial self-improving charge storage capacities as cycling proceeds, leading to a specific capacity of 202.2 ± 50.6 mAh g −1 at a current rate of 30 mA g −1 (C/20). Subsequent kinetic analysis reveals a pseudocapacitive contribution which dominates the Na storage process in TiO 2−x −C nanotubes at fast sodiation rates. This pseudocapacitance in TiO 2−x −C nanotubes is found to enable exceptional high-rate capabilities with a specific capacity of 58.4 ± 14.6 mAh g −1 at a current rate of 12 A g −1 (20C).

Interactions occurring during the surfactant‐enhanced foliar uptake of seven model organic compounds were examined using two homogeneous surfactants, hexaethylene glycol monotridecyl ether (C13E6) and hexadecaethylene glycol monododecyl ether (C12E16). Surfactant–compound and compound–surfactant interactions were detected by measurement of their relative uptake rates following application of c. 0·2 μl droplets of the corresponding radiolabelled formulations. The magnitude of surfactant–compound interaction was found to vary according to the physicochemical properties of both the compound and the surfactant, and was influenced by surfactant concentration and target plant species. Interactive and non‐interactive mechanisms, both leading to substantial enhancement of compound uptake, could be identified, but their precise nature could not be elucidated. Although penetration of C13E6 into the site of application appeared to be essential in order to activate the uptake of a compound, substantial absorption of C12E16 was not always required to produce the same effect. The results are discussed in the light of possible sites and modes of action for activator polyoxyethylene surfactant adjuvants.

Composition‐concentration relationships between a series of C13/C14 polyoxyethylene primary alcohol (AE) surfactants and the foliar uptake enhancement of five model neutral organic compounds were examined in factorially designed experiments on wheat (Triticum aestivum L.) and field bean (Vicia faba L.) plants grown under controlled environment conditions. Model compounds were applied to leaves as c.0.2‐μl droplets of 0.5 g litre−1 solutions in aqueous acetone in the absence or presence of surfactants at 0.2, 1 and 5g litre−1. Uptake of the highly water‐soluble compound, methylglucose (log octanol‐water partition coefficient (P) = ‐ 3.0) was best enhanced by surfactants with high E (ethylene oxide) contents (AE15, AE20), whereas those of the lipophilic compounds, WL110547 (log P = 3.5) and permethrin (log P = 6.5), were increased more by surfactants of lower E contents, especially AE6. However, there was little difference between AE6, AE11, AE15 and AE20 in their ability to promote uptake of the two model compounds of intermediate polarity, phenylurea (log P = 0.8) and cyanazine (log P = 2.1). Absolute amounts of compound uptake were also influenced strongly by both surfactant concentration and plant species. Greatest amounts of uptake enhancement were often observed at high surfactant concentration (5 g litre−1) and on the waxy wheat leaves compared with the less waxy field bean leaves. The latter needed higher surfactant thresholds to produce significant improvements in uptake. Data from our experiments were used to construct a simple response surface model relating uptake enhancement to the E content of the surfactant added and to the physicochemical properties of the compound to be taken up. Qualitative predictions from this model might be useful in rationalising the design of agrochemical formulations.

The physicochemical properties of adjuvants determine their function and impact upon biological activity. Various physicochemical parameters are key to modifying both the preretention events and postretention consequences of adjuvant usage, irrespective of whether the adjuvants are tank-mix additives or built into a formulation. This paper discusses several key adjuvant parameters for a range of adjuvant chemistries alone and in mixtures. In addition, the misleading use of terms such as nonionic surfactant and hydrophile–lipophile balance is addressed. From a more coherent understanding of the parameters involved, it can be shown that there are ways of predicting the required properties of an adjuvant to solve specific delivery problems. The recognition that different problems often require quite different approaches illustrates that good adjuvants do not exist per se, only materials that should be rationally selected for specific reasons. The chemistry of the herbicide and the nature of its targets will dictate adjuvant selection criteria.

How the biophysical properties of overlaying tissues control growth, such as the embryonic root (radicle) during seed germination, is a fundamental question. In eudicot seeds the endosperm surrounding the radicle confers coat dormancy and controls germination responses through modulation of its cell wall mechanical properties. Far less is known for grass caryopses that differ in tissue morphology. Here we report that the coleorhiza, a sheath-like organ that surrounds the radicle in grass embryos, performs the same role in the grass weed Avena fatua (common wild oat). We combined innovative biomechanical techniques, tissue ablation, microscopy, tissuespecific gene and enzyme activity expression with the analysis of hormones and oligosaccharides. The combined experimental work demonstrates that in grass caryopses the coleorhiza indeed controls germination for which we provide direct biomechanical evidence. We show that the coleorhiza becomes reinforced during dormancy maintenance and weakened during germination. Xyloglucan endotransglycosylases/hydrolases may have a role in coleorhiza reinforcement through cell wall remodelling to confer coat dormancy. The control of germination by coleorhiza-enforced dormancy in grasses is an example of the convergent evolution of mechanical restraint by overlaying tissues.

Long term galvanostatic charge/discharge cycling of oxygen deficient, carburized and self‐organized titanium dioxide (TiO2) nanotubes (NTs) in sodium ion (Na) batteries (SIBs) are subject to a significant self‐improving charge storage behavior. Surface reactions upon sodiation of carburized NTs form acicular surface films that can be reversibly cycled. We show that, alongside organic species from the decomposition of the electrolyte, mainly inorganic compounds, such as Na2O2 and Na2CO3, are the main constituents. These components possess a characteristic acicular morphology. Na2O2 is found to form upon sodiation and converted to NaO2 upon desodiation. This, in combination with its pseudo‐capacitive charge storage characteristics, explains the excellent rate capability measured for TiO2‐x‐C NTs. The observed high reversibility of this surface chemistry is also essential for the fast kinetics and the high capacity retention found in the system. Our findings point to a more general Na‐ion storage mechanism, that is potentially relevant to other transition metal oxides also.