Effect of vessel wettability on the foamability of "ideal" surfactants and "real-world" beer heads

The ability to tailor the foaming properties of a solution by controlling its chemical composition is highly desirable and has been the subject of extensive research driven by a range of applications. However, the control of foams by varying the wettability of the foaming vessel has been less widely reported. This work investigates the effect of the wettability of the side walls of vessels used for the in situ generation of foam by shaking aqueous solutions of three different types of model surfactant systems (non-ionic, anionic and cationic surfactants) along with four different beers (Guinness Original, Banks’s Bitter, Bass No 1 and Harvest Pale). We found that hydrophilic vials increased the foamability only for the three model systems but increased foam stability for all foams except the model cationic system. We then compared stability of beer foams produced by shaking and pouring and demonstrated weak qualitative agreement between both foam methods. We also showed how wettability of the glass controls bubble nucleation for beers and champagne and used this effect to control exactly where bubbles form using simple wettability patterns

Effect of Particle Size on Droplet Infiltration into Hydrophobic Porous Media As a Model of Water Repellent Soil

The wettability of soil is of great importance for plants and soil biota, and in determining the risk for preferential flow, surface runoff, flooding,and soil erosion. The molarity of ethanol droplet (MED) test is widely used for quantifying the severity of water repellency in soils that show reduced wettability and is assumed to be independent of soil particle size. The minimum ethanol concentration at which droplet penetration occurs within a short time (≤10 s) provides an estimate of the initial advancing contact angle at which spontaneous wetting is expected. In this study, we test the assumption of particle size independence using a simple model of soil, represented by layers of small (0.2–2 mm) diameter beads that predict the effect of changing bead radius in the top layer on capillary driven imbibition. Experimental results using a three-layer bead system show broad agreement with the model and demonstrate a dependence of the MED test on particle size. The results show that the critical initial advancing contact angle for penetration can be considerably less than 90° and varies with particle size, demonstrating that a key assumption currently used in the MED testing of soil is not necessarily valid

Passive water control at the surface of a superhydrophobic lichen

Some lichens have a super-hydrophobic upper surface, which repels water drops, keeping the surface dry but probably preventing water uptake. Spore ejection requires water and is most efficient just after rainfall. This study was carried out to investigate how super-hydrophobic lichens manage water uptake and repellence at their fruiting bodies, or podetia. Drops of water were placed onto separate podetia of Cladonia chlorophaea and observed using optical microscopy and cryo-scanning-electron microscopy (cryo-SEM) techniques to determine the structure of podetia and to visualise their interaction with water droplets. SEM and optical microscopy studies revealed that the surface of the podetia was constructed in a three-level structural hierarchy. By cryo-SEM of water-glycerol droplets placed on the upper part of the podetium, pinning of the droplet to specific, hydrophilic spots (pycnidia/apothecia) was observed. The results suggest a mechanism for water uptake, which is highly sophisticated, using surface wettability to generate a passive response to different types of precipitation in a manner similar to the Namib Desert beetle. This mechanism is likely to be found in other organisms as it offers passive but selective water control

'If You Desire to Enjoy Life, Avoid Unpunctual People': Women, Timetabling and Domestic Advice, 1850–1910

In the second half of the nineteenth century domestic advice manuals applied the language of modern, public time management to the private sphere. This article uses domestic advice and cookery books, including Isabella Beeton's Book of Household Management, to argue that women in the home operated within multiple, overlapping temporalities that incorporated daily, annual, linear and cyclical scales. I examine how seasonal and annual timescales coexisted with the ticking clock of daily time as a framework within which women were instructed to organize their lives in order to conclude that the increasing concern of advice writers with matters of timekeeping and punctuality towards the end of the nineteenth century indicates not the triumph of 'clock time' but rather its failure to overturn other ways of thinking about and using time

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Utilization of nanostructured surfaces for sensing applications and the use of nanoentities for the fabrication of new materials

The application of nanoscience in various scientific fields is introduced in Chapter 1 by outlining some of the major drivers of this rapidly evolving field. Methods of nanoscale fabrication, utilizing both 'top-down' and 'bottom-up' approaches, are also introduced in this chapter. Nanoscale characterization techniques that allow the visualization of the 'nanoworld' are introduced in Chapter 2. Chapter 3 is concerned with the modification of Si$_3$N$_4$ substrates with self-assembled monolayers (SAMs) of 3-aminopropyltrimethoxysilane (APTMS) via a vapour deposition method. This investigation was carried out by forming APTMS SAMs, from the solution phase, on both SiO$_2$ and Si$_3$N$_4$ substrates and comparing them to provide a model with which to compare SAMs formed by a novel vapour phase methodology. Chapter 4 further develops the work from Chapter 3 by chemically modifying Si$_3$N$_4$ resonators with APTMS SAMs via vapour deposition. The chemically modified resonators were then used for the mass detection of citrate passivated Au nanoparticles and the results were compared to AFM and XPS studies of the same system but on planar substrates. Chapter 5 is concerned with the fabrication of a bioarray for the patterned immobilization of human spermatozoa cells. Such arrays would allow for the investigation of specific individual sperm cells. This could have a use in the field of artificial insemination. Chapter 6 utilizes citrate passivated Au nanoparticles to prepare composite PEO/Au nanoparticle solutions for the formation of sub-micron diameter electrospinning. Such fibres are electrospun from solutions of 4 different concentrations of PEO and then subsequently characterized by optical microscopy, AFM, TEM and DSC

Effect of Particle Size on Droplet Infiltration into Hydrophobic Porous Media As a Model of Water Repellent Soil

The wettability of soil is of great importance for plants and soil biota, and in determining the risk for preferential flow, surface runoff, flooding,and soil erosion. The molarity of ethanol droplet (MED) test is widely used for quantifying the severity of water repellency in soils that show reduced wettability and is assumed to be independent of soil particle size. The minimum ethanol concentration at which droplet penetration occurs within a short time (≤10 s) provides an estimate of the initial advancing contact angle at which spontaneous wetting is expected. In this study, we test the assumption of particle size independence using a simple model of soil, represented by layers of small (∼0.2–2 mm) diameter beads that predict the effect of changing bead radius in the top layer on capillary driven imbibition. Experimental results using a three-layer bead system show broad agreement with the model and demonstrate a dependence of the MED test on particle size. The results show that the critical initial advancing contact angle for penetration can be considerably less than 90° and varies with particle size, demonstrating that a key assumption currently used in the MED testing of soil is not necessarily valid

Fragment-Based Discovery of Type I Inhibitors of Maternal Embryonic Leucine Zipper Kinase

Fragment-based drug design was successfully applied to maternal embryonic leucine zipper kinase (MELK). A low affinity (160 μM) fragment hit was identified, which bound to the hinge region with an atypical binding mode, and this was optimized using structure-based design into a low-nanomolar and cell-penetrant inhibitor, with a good selectivity profile, suitable for use as a chemical probe for elucidation of MELK biology

Pyridyl-2,5-Diketopiperazines as Potent, Selective, and Orally Bioavailable Oxytocin Antagonists: Synthesis, Pharmacokinetics, and In Vivo Potency

A six-stage stereoselective synthesis of indanyl-7-(3′-pyridyl)-(3<i>R</i>,6<i>R</i>,7<i>R</i>)-2,5-diketopiperazines oxytocin antagonists from indene is described. SAR studies involving mono- and disubstitution in the 3′-pyridyl ring and variation of the 3-isobutyl group gave potent compounds (p<i>K</i>_i > 9.0) with good aqueous solubility. Evaluation of the pharmacokinetic profile in the rat, dog, and cynomolgus monkey of those derivatives with low cynomolgus monkey and human intrinsic clearance gave 2′,6′-dimethyl-3′-pyridyl <i>R</i>-<i>sec</i>-butyl morpholine amide Epelsiban (<b>69</b>), a highly potent oxytocin antagonist (p<i>K</i>_i = 9.9) with >31000-fold selectivity over all three human vasopressin receptors hV1aR, hV2R, and hV1bR, with no significant P450 inhibition. Epelsiban has low levels of intrinsic clearance against the microsomes of four species, good bioavailability (55%) and comparable potency to atosiban in the rat, but is 100-fold more potent than the latter in vitro and was negative in the genotoxicity screens with a satisfactory oral safety profile in female rats