On the theory of surface waves in water generated by moving disturbances

The wave profile generated by an obstacle moving at constant veiocity U over a water surface of infinite extent appears to be stationary with respect to the moving body provided, of course, the motion has been maintained for a long time. When the gravitational and capillary effects are both taken into account, the surface waves so generated may possess a minimum phase velocity c[sub]m characterized by a certain wave length, say [lambda][sub]m (see Ref. 1, p. 459). If the velocity U of the solid body is greater than c[sub]m, then the physically correct solution of this two-dimensional problem requires that the gravity waves (of wave length greater than [lambda][sub]m) should exist only on the downstream side and the capillary waves (of wave length less than [lambda][sub]m) only on the upstream side. If one follows strictly the so-called steady-state formulation so that the time does not appear in the problem, one finds in general that it is not possible to characterize uniquely the mathematical solution with the desired physical properties by imposing only the boundedness conditions at infinity. [Footnote: In the case of a three-dimensional steady-state problem, even the condition that the disturbance should vanish at infinity is not sufficient to characterize the unique solution.] Some stronger radiation conditions are actually necessary. In the linearized treatment of this stationary problem, several methods have been employed, most of which are aimed at obtaining the correct solution by introducing some artificial device, either of a mathematical or physical nature. One of these methods widely used was due to Rayleigh, and was further discussed by Lamb. In the analysis of this problem Rayleigh introduced a "small dissipative force", proportional to the velocity relative to the moving stream. This "law" of friction does not originate from viscosity and is hence physically fictitious, for in the final result this dissipation factor is made to vanish eventually. In the present investigation, Rayleigh's friction coefficient is shown to correspond roughly to a time convergence factor for obtaining the steady-state solution from an initial value problem. (It is not a space-limit factor for fixing the boundary conditions at space infinity, as has usually been assumed in explanation of its effect). Thus, the introduction of Rayleigh's coefficient is only a mathematical device to render the steady-state solution mathematically determinate and physically acceptable. For a physical understanding, however, it is confusing and even misleading; for example, in an unsteady flow case it leads to an incomplete solution, as has been shown by Green. Another approach, purely of a physical nature, was used by Michell in his treatment of the velocity potential for thin ships. To make the problem determinate, he chose the solution which represents the gravity waves propagating only downstream and discarded the part corresponding to the waves traveling upstream. For two-dimensional problems with the capillary effect, this method would mean a superposition of simple waves so as to make the solution physically correct. Some other methods appear to be limited in the necessity of interpreting the principal value of a certain kind of improper integral. In short, as to their physical soundness and mathematical rigor, or even to their merits or demerits, the preference of one method over the others has remained nevertheless a matter of considerable dispute. Only until recently the steady-state problem has been treated by first formulating a corresponding initial value problem. A brief historical sketch of these methods is given in the next section. The purpose of this paper is to try to understand the physical mechanism underlying the steady configuration of the surface wave phenomena and to clarify to a certain extent the background of the artifices adopted for solution of steady-state problems. The point of view to be presented here is that this problem should be formulated first as an initial value problem (for example, the body starts to move with constant velocity at a certain time instant), and then the stationary state is sought by passing to the limit as the time tends to infinity. If at any finite time instant the boundary condition that the disturbance vanishes at infinity (because of the finite wave velocity) is imposed, then the limiting solution as the time tends to infinity is determinate and bears automatically the desired physical properties. Also, from the integral representation of the linearized solution, the asymptotic behavior of the wave form for large time is derived in detail, showing the distribution of the wave trains in space. This asymptotic solution exhibits an interesting picture which reveals how the dispersion* generates two monochromatic wave trains, with the capillary wave in front of, and the gravity wave behind, the surface pressure. *[Footnote: By dispersive medium is meant one in which the wave velocity of a propagating wave depends on the wave length, so that a number of wave trains of different wave lengths tends to form groups, propagating with group velocities which are in general different from the phase velocities of individual wave trains. In case of waves on the water surface, both the gravity and surface tension are responsible for dispersion.] The special cases U< c[sub]m and U = c[sub]m are also discussed. The viscous effect and the effect of superposition are commented upon later. Through this detailed investigation it is found that the dispersive effect, not the viscous effect plays the significant role in producing the final stationary wave configuration

OpenAdaptxt: an open source enabling technology for high quality text entry

Modern text entry systems, especially for touch screen phones and novel devices, rely on complex underlying technologies such as error correction and word suggestion. Furthermore, for global deployment a vast number of languages have to be supported. Together this has raised the entry bar for new text entry techniques, which makes developing and testing a longer process thus stifling innovation. For example, testing a new feedback mechanism in comparison to a stock keyboard now requires the researchers to support at least slip correction and probably word suggestion. This paper introduces OpenAdaptxt: an open source community driven text input platform to enable development of higher quality text input solutions. It is the first commercial-grade open source enabling technology for modern text entry that supports both multiple platforms and dictionary support for over 50 spoken languages

MS

thesisA descriptive correlation study was conducted with 110 postoperative coronary artery bypass graft (CABG) patients at the Naval Regional Medical Center, San Diego, California. The purpose of the research project was to determine the occurrence of depression in coronary artery bypass graft (CABG) patients who were up to 12-months post surgery, establish a common time of occurrence and identify any relationships of variables with coronary artery bypass graft (CABG) surgery and depression. A mail survey was utilized an questionnaire packets were mailed simultaneously to subject. Evidence of depression was based on scores from the Zung Self-Rating Depression Scale, while relationships between variables were identified from information obtained from a personal profile questionnaire. Statistical analysis revealed 18.6% of the sample clinically depressed. The use of an exclusive military sample somewhat limited the comparison of the findings to the national depression occurrence of 17.3% of the general population. However, there was a positive finding of higher depression scores within the first one to three months following CABG surgery. Furthermore, statistically significant relationships were found between satisfaction with surgical outcome, felling as well as expected and the number of postoperative complications, with findings of depression in CABG patients

Solid and Semisolid Innovative Formulations Containing Miconazole-Loaded Solid Lipid Microparticles to Promote Drug Entrapment into the Buccal Mucosa

The currently available antifungal therapy for oral candidiasis (OC) has various limita- tions restricting its clinical use, such as short retention time, suboptimal drug concentration and low patients compliance. These issues could be overcome using micro or nanotechnology. In par- ticular, solid lipid microparticles (SLMs) resulted as a particularly promising penetration enhancer carrier for lipophilic drugs, such as the antifungal miconazole (MCZ). Based on these considera- tions, cetyl decanoate (here synthesized without the use of metal catalysis) was employed together with 1-hexadecanol to prepare MCZ-loaded SLMs. These resulted in a powder composed of 45–300 µm diameter solid spherical particles, able to load a high amount of MCZ in the amorphous form and characterized by a melting temperature range perfectly compatible with oromucosal admin- istration (35–37 °C). Moreover, when compared to Daktarin ® 2% oral gel in ex vivo experiments, SLMs were able to increase up to three-fold MCZ accumulation into the porcine buccal mucosa. The prepared SLMs were then loaded into a buccal gel or a microcomposite mucoadhesive buccal film and evaluated in terms of MCZ permeation and/or accumulation into porcine buccal mucosa by using lower doses than the conventional dosage form. The promising results obtained high- lighted an enhancement in terms of MCZ accumulation even at low doses. Furthermore, the pre- pared buccal film was eligible as stable, reproducible and also highly mucoadhesive. Therefore, the formulated SLMs represent a penetration enhancer vehicle suitable to reduce the dose of lipophilic drugs to be administered to achieve the desired therapeutic effects, as well as being able to be ef- fectively embedded into easily administrable solid or semisolid dosage forms

Buccal Thin Films as Potent Permeation Enhancers for Cytisine Transbuccal Delivery

Cytisine (CYT) is a powerful anti-smoking compound which could greatly benefit from transbuccal delivery because of both its unfavorable pharmacokinetics after oral administration and its intrinsic ability to permeate the buccal mucosa. This work aims to design CYT-loaded buccal thin films suitable for transbuccal drug delivery due to its capability of promoting the interaction between CYT and the buccal membrane. The solvent casting method was employed to prepare several thin films combining various excipients such as matrixing polymers, mucoadhesion agents, plasticizers and other compounds as humectants and sweeteners, component ratios and solvents. A total of 36 compositions was prepared and four of them emerged as the most promising in terms of aspect and flexibility. They all demonstrated homogeneity, thinness, low swelling degree, and controlled drug release according to the Power Law and Peppas-Sahlin mathematical models. Mainly, they proved able to interact with the ex vivo porcine buccal mucosa producing mucoadhesive effects, and act as potent permeation enhancers. In particular, Film B emerged as suitable as it produced a 10.6-fold Kp enhancement and a great Js value (52.33 μg/cm2·h-1), even when compared to highly concentrated CYT solutions

Green next generation biomaterials from virtuous recovery of grape processing waste bentonite

The waste valorisation, by conversion of discharge products into novel high value-added biomaterials, represents a virtuous strategy to contribute to the ecological transition while producing social, economic and scientific repercussions. Even more, the recycle of wastes from the local resources could maximize the impact of the circular economy idea by enhancing the territorial resources and creating new products free from additional raw materials consumption. About this, the grape processing industry is an undoubted Sicilian prestige, but it also produces abundant both organic and inorganic wastes. While grape pomace has been extensively valorised in the last years, the inorganic wastes have never been considered yet. The latter are mainly the fining agents, among which bentonite is the most common one. It is a mineral clay widely used due to low cost, abundance in nature, high clarifying power and ease of separation from the fined product by sedimentation. So far, the bentonite is just an abundant waste (100g of bentonite to fine 1hL of must/wine) then the aim of this work is to recognize it as a precious source of polyphenols to be given new life by extraction. The frozen waste black bentonite was supplied by Bono&amp;Ditta S.p.A. Once arrived at the University of Palermo it was subjected to pulverization, sieved, divided into aliquots identified as belonging to the same lot and stored at -80°C. Samples of bentonite were subjected to green extraction by maceration (1h, 25°C, constant stirring, in the dark) choosing unconventional extraction solvents among well-known and currently used hydrophilic liquid excipients for pharmaceuticals and cosmetics. They were PEGs (PEG200, PEG400, PEG600), propylene glycol and glycerine, selected due to their high solvent power toward polyphenols and biocompatibility. The coloured liquid extracts were characterized and compared in terms of antioxidant power/scavenging activity by DPPH assay, chromatographic profile and extracted amount of some representative polyphenols by HPLC-DAD analyses, total phenolic and protein contents by Folin-Ciocalteu and Bradford assays respectively. The best extract was obtained by using PEG200 and was then further studied. It resulted stable at easily achievable storage conditions (4°C, in the dark) for at least 6 months. Furthermore, it is suitable as a novel, value-added biomaterial for biomedical and cosmetic purposes as nor skin/eye irritation neither skin sensitising potential emerged by the in vitro tests, according to OECD 439/492/442E guidelines. Importantly, the “green soul” of this work is not just related to waste bentonite valorisation. The extraction procedure can be considered eco-friendly both in terms of employed technique and chosen extraction solvents. This choice perfectly fit with an industrial, easily scalable and waste-to-market approach as well as with the SDGs 12, 8 and 3 of the UN agenda 2030

Angústia com vertigem da liberdade: Kierkegaard e a trilogia do silêncio de Bergman

Este trabalho pretende se aproximar da angústia existencial sob a ótica da filosofia de Søren Aabye Kierkegaard e do cinema de Ingmar Bergman, especificamente os três filmes que compõem a Trilogia do Silêncio. Dada a interlocução de suas obras mediante pensamentos ressonantes, a monografia apresentada propõe explorar também os pontos de cisão entre os autores no que diz respeito à angústia e às inquietações que por ela são envolvidas. Para tanto, desvinculou-se a relação de sujeição de uma obra a outra; ao contrário, admitiu-se tanto as imagens quanto as palavras como instâncias autônomas e potentes na produção – ou potencialização – da questão. Assim como o campo de subjetividade em que Bergman e Kierkegaard operam relativiza quaisquer conceitos ou conclusões, também este projeto não se dispõe a encontrar respostas para a problemática levantada, mas apenas apontar leituras possíveis

Improvement of resveratrol permeation through sublingual mucosa: Chemical permeation enhancers versus spray drying technique to obtain fast-disintegrating sublingual mini-tablets

Resveratrol (RSV) is a natural polyphenol with several interesting broad-spectrum pharmacological properties. However, it is characterized by poor oral bioavailability, extensive first-pass effect metabolism and low stability. Indeed, RSV could benefit from the advantage of the sublingual route of administration. In this view, RSV attitudes to crossing the porcine sublingual mucosa were evaluated and promoted both by six different chemical permeation enhancers (CPEs) as well as by preparing four innovative fast-disintegrating sublingual mini-tablets by spray drying followed by direct compression. Since RSV by itself exhibits a low permeation aptitude, this could be significantly enhanced by the use of CPEs as well as by embedding RSV in a spray-dried powder to be compressed in order to prepare fast-disintegrating mini-tablets. The most promising observed CPEs (menthol, lysine and urea) were then inserted into the most promising spray-dried excipients’ compositions (RSV-B and RSV-C), thus preparing CPE-loaded mini-tablets. However, this procedure leads to unsatisfactory results which preclude the possibility of merging the two proposed approaches. Finally, the best spray-dried composition (RSV-B) was further evaluated by SEM, FTIR, XRD and disintegration as well as dissolution behavior to prove its effectiveness as a sublingual fast-disintegrating formulation

Lipid Nanoparticles Loaded With Resveratrol And Glycyrrhetinic Acid As New Tool For Wound Healing

Skin and mucous membranes maintain the homeostasis of the full body and are the first barriers against microbial infections. Therefore, their integrity is crucial and any lesion or injury must be quickly treated. In healthy people, several steps, such as inflammation, production of pro-oxidative species, cells proliferation and remodelling, follow each other creating a cascade process that determine the total restoration of the injured tissue. However, even a single discrepancy in these phases can delay the wound healing or irreversibly compromise the tissue. A smart strategy to promote wound healing could be the administration of natural compounds such as polyphenols and triterpenoids which are characterized by strong antioxidant and anti-inflammatory activities, antimicrobial properties and low side effects. However, the beneficial effects of these molecules are limited by their disadvantageous physico-chemical properties (e.g., low solubility in water, degradation) that compromise their bioavailability and thereby their clinical use. Based on these considerations, the aim of this work was to prepare and characterize a novel drug delivery system in form of multicomponent lipid nanoparticles (LNPs) constituted by a complex mixture of PEGylated lipid, Glyceryl monoester and Menthol able to entrap the polyphenol Resveratrol (RSV) and the triterpenoid Glycyrrhetinic Acid (GA) in order to protect them from degradation and maximize their effectiveness so as to make them useful for the wound management. Following optimization of the lipid blend composition and excipient ratios, it resulted homogeneous, with a melting range temperature of 57-61°C and containing GA (2.73 ± 0.23%w/w) and RSV (4.56 ± 0.04%w/w) in the amorphous form. The LNPs, obtained by homogenization followed by high-frequency sonication, were characterized by DLS and SEM analyses resulting almost monodispersed (PDI: 0.267 ± 0.010), with spherical shape (by SEM), nanometric size (162.86 ± 3.12nm) and suitable Z-potential (-21.40 ± 7.33mV). The quantitative analyses showed high encapsulation efficiency for both RSV and GA having a suitable DR% (96.82 ± 1.34% and 99.6 ± 1.29%, respectively) and LE% (96.82 ± 1.34% and 97.15 ± 0.19%, respectively) values. RSV release studies highlighted a sustained and controlled pattern of discharge to different chemical environments simulating the wound conditions. Moreover, LNPs showed significant scavenger properties evaluated by the DPPH assay. Last, the biological evaluations (scratch assay) highlighted an enhanced fibroblasts proliferation and migration at extremely low doses (LNPs 22 μg/mL corresponding to RSV 5 μM). Furthermore, a promising antibiofilm effect against Staphilococcus aureus was observed in a dose-dependent manner. In conclusion, these novel multicomponent LNPs could represent a next generation carrier constituting a promising tool for wound healing purposes