Fiber-parenchyma trade-off underlies changes in tropical forest structure and xylem architecture across a soil water gradient

Wood anatomical traits can underpin tropical forest structural and functional changes across soil water gradients and therefore could improve our mechanistic understanding of how plants adapt to environmental change. We assessed how the variation in the forest maximum height (Hmax), stem diameter, and wood density (WD) is associated with variation in xylem traits (area of fibers and parenchyma, conductive area [CondA, sum of all vessels lumens], vessel lumen area [VLA], vessel density [VD], and vessel wall reinforcement [VWR]) across 42 plots of a Brazilian Atlantic Forest habitat that span strong soil water gradients. We found that in wetter communities, greater height and lower WD were associated with greater parenchyma area (capacitance), and lower fibers, VD, VWR. Contrastingly, in drier communities, lower height was associated with higher fiber area (xylem reinforcement), WD, VD, and VWR, while parenchyma area and vessels are reduced. Tree communities vary from conservative resource-use and structurally dependent hydraulic safety (Fibers) to acquisitive resource-use and capacitance dependent hydraulic safety (parenchyma). Such a fiber-parenchyma trade-off (FPT) underlies the variation in tree height across a soil water gradient. Wood anatomy is fundamental to understanding and predicting the impacts of environmental change on forest structure.

Topical formulations, design and drug delivery: "A dive into water"

Water is a vital component regulating the properties of topical formulations and their interaction with biological barriers, such as skin and mucosa. Changing the watercontent within the frame of the pharmaceutical triangle will have a huge impact on which type of formulation, such as a cream, ointment, gel, or lotion, is formed, as well as the physical properties of the formulation. The composition of a formulation, and the subsequent reformulation after application, will govern the features of the residual film. This will in turn affect the barrier properties of the underlying tissue and consequently the penetration of various substances across skin or mucosa.The primary aim of this thesis has been to provide further understanding on differences between traditional surfactant-based formulations and particle-stabilized, Pickering, formulations and how specific excipients, like alcohols, emollients, and thickeners can affect their physical and/or sensorial properties. The secondary aim has been to gain more knowledge on the role of water in topical formulations and how it affects the properties of the underlaying tissue on application. By combining a portfolio of physicochemical techniques combined with sensory science, we have been able to identify differences between Pickering and surfactantstabilized formulations. Starch-based Pickering emulsions were perceived as less greasy and sticky than traditional creams, even at high oil content. Moreover, we were able develop a novel type of alcohol-based Pickering emulsion with combined moisturizing and antiseptic properties. We have also been able to link sensory attributes, evaluated by human volunteers, with physicochemical characterizations. Furthermore, the in vitro ForceBoard™ method was developed further and we evaluated its potential to be used as an ex vivo method using excised skin. In addition, we have shown that that the water gradient over a biological barrier has a general relevance with respect to drug absorption and should be considered not only in dermaldrug delivery but also for buccal and nasal drug delivery.

Interaction between siloxane-hydrogel contact lenses and eye cosmetics: Aluminum as a marker of adsorbed mascara deposits

The purpose of the study was to investigate the presence of mascara deposits on polymeric siloxane-hydrogel contact lenses (CLs) after in vivo 8 h of wear and to compare the affinity to mascara of two siloxane-hydrogels through in vitro contamination tests. The siloxane-hydrogel CLs were the Filcon V monthly replacement OPEN30 and the Delefilcon A daily disposable DAILIES TOTAL1 showing a water gradient from the core to the outermost hydrophilic surface layer. The investigated cosmetic was a blue mascara. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were carried out on new CLs, CLs exposed in vitro to mascara, and CLs worn for 8 h by mascara wearers (after rinsing the CLs in sodium chloride solution). Images by an optical microscope were acquired and processed on new CLs and CLs treated in vitro. EDX analyses on mascara allowed to characterize its elemental composition including aluminum (Al), which is neither a tear nor a CL component, thus being a marker of the presence of mascara deposits on polymeric siloxane-hydrogels. Adsorbed deposits containing Al were observed by SEM/EDX on all worn CLs of both materials, which showed a special affinity for the mascara components, more marked than for the tear components. By processing the images taken by optical microscopy after in vitro tests, the presence of mascara deposits was found to be more than two times higher in Delefilcon A compared to Filcon V CLs.

Performance of Daily Disposable Contact Lenses in Symptomatic Wearers

PurposeTo evaluate the performance of delefilcon A water gradient and narafilcon A silicone hydrogel daily dispos-able contact lenses (CLs) in symptomatic soft CL wearers. MethodsThis multicenter, open-label, crossover study randomized 121 soft CL wearers with symptoms of CL dis-comfort to delefilcon A or narafilcon A for 2 weeks, followed by the alternate lens for 2 weeks. Subjects rated end-of-day (EOD) comfort, EOD dryness, and quality of vision, and investigators rated fit, surface deposits, and surface wettability. ResultsAfter 2 weeks, all subjective measures were better for delefilcon A than for narafilcon A, including EOD comfort (8.3 ± 1.9 vs. 6.6 ± 2.2), EOD dryness (8.0 ± 2.2 vs. 5.8 ± 2.6), and quality of vision (8.9 ± 1.4 vs. 7.9 ± 1.7), all p<.0001. Average daily wear time (DWT; 13.0 ± 2.8 vs. 12.3 ± 2.6 hr) and average comfort-able DWT (11.6 ± 3.9 vs. 9.3 ± 3.8 hr) were longer for delefilcon A lenses (p<.0001). The proportions of right and left lenses without front surface deposits were twofold higher for delefilcon A than for narafilcon A, and surface wettability was significantly higher for delefilcon A than for narafilcon A p<.0001). ConclusionIn this population of symptomatic CL wearers, delefilcon A lenses showed superior subjective ratings for comfort, dryness, quality of vision, DWT, and comfortable DWT and better investigator-rated lens sur-face attributes including fewer surface deposits and superior wettability than did narafilcon A lenses after 2 weeks of wear.