101 research outputs found
Exploiting Amorphous Data Parallelism to Speed-Up Massive Time-Dependent Shortest-Path Computations
No full textWe aim at exploiting parallelism in shared-memory multiprocessing systems, in order to speed up the execution time with as small redundancy in work as possible, for an elementary task that comes up frequently as a subroutine in the daily maintenance of large-scale time-dependent graphs representing real-world relationships or technological networks: the many-to-all time-dependent shortest paths (MATDSP) problem. MATDSP requires the computation of one time-dependent shortest-path tree (TDSPT) per origin-vertex and departure-time, from an arbitrary collection of pairs of origins and departure-times, towards all reachable destinations in the graph.
Our goal is to explore the potential and highlight the limitations of amorphous data parallelism, when dealing with MATDSP in multicore computing environments with a given amount of processing elements and a shared memory to exploit. Apart from speeding-up execution time, consumption of resources (and energy) is also critical. Therefore, we aim at limiting the work overhead for solving a MATDSP instance, as measured by the overall number of arc relaxations in shortest-path computations, while trying to minimize the overall execution time. Towards this direction, we provide several algorithmic engineering interventions for solving MATDSP concerning: (i) the compact representation of the instance; (ii) the choice and the improvement of the time-dependent single-source shortest path algorithm that is used as a subroutine; (iii) the way according to which the overall work is allocated to the processing elements; (iv) the adoption of the amorphous data parallelism rationale, in order to avoid costly synchronization among the processing elements while doing their own part of the work.
Our experimental evaluations, both on real-world and on synthetic benchmark instances of time-dependent road networks, provide insight how one should organize heavy MATDSP computations, depending on the application scenario. This insight is in some cases rather unexpected. For instance, it is not always the case that pure data parallelism (among otherwise totally independent processors) is the best choice for minimizing execution times. In certain cases it may be worthwhile to limit the level of data parallelism in favor of algorithmic parallelism, in order to achieve more efficient MATDSP computations
A Novel GO Analysis Tool for GRIN Lenses based on the Fast Sweeping Method
No full textAdditive manufacturing has facilitated the straightforward development and prototyping of Graded Index (GRIN) lenses. These lenses are constructed using inhomogeneous dielectric materials and leverage a refractive index gradient to manipulate the path of light within the lens. This technology allows for creating lenses with flat surfaces and a high level of design flexibility. The Fast Sweeping Method (FSM) is a numerical approach designed to efficiently address both wavefront propagation and field amplitude in GRIN lenses. The utility of the FSM is evaluated by establishing its accuracy and effectiveness, making it a viable alternative to traditional ray-tracing methods. Due to its robust performance, FSM emerges as a strong candidate for serving as the analytical engine in an optimization process for the automatic design of GRIN lenses
GO Analysis of GRIN Lens Antennas by Combining in a Single ODE, Field and Wavefront-Curvature Transport to the Ray Tracing
No full textA novel very efficient algorithm based on geometrical optics (GO) is presented for the analysis of graded index (GRIN) lens antennas, namely, dielectric inhomogeneous lenses with a 3-D arbitrary varying refractive index. A family of curved ray paths are traced starting from a set of points defined on the lens input interface, which is illuminated by a feed antenna, up to a corresponding set of points on the output interface, i.e., the lens radiating aperture. The ray tracing is numerically performed in combination with the field transportation along the ray by exploiting an additional wavefront-curvature transport equation, thus providing a single independent vector ordinary differential equation (ODE) for each ray. This scheme allows a complete parallelization of the algorithm by assigning any ray to a different thread. Crossing the lens input–output interfaces at the two end points of the curved ray is accomplished by augmenting the refraction Snell’s law and the Fresnel transmission coefficients with a novel compact closed-form dyadic formula for the transmitted wavefront curvature. The ODE output provides the field aperture distribution on the output lens interface, permitting the far-field calculation as a radiation integral. To this end, an ad hoc quadrature rule is exploited, which requires an aperture sampling rate corresponding to the slowly varying part of the integrand, while the rapid phase variation is accounted for analytically, thus resulting in an extremely efficient and frequency-independent scheme. The effectiveness and accuracy of the algorithm are shown by resorting to a couple of well-known analytical benchmarks and to two more general examples with real-life antennas: a spaceborne weather radar lens antenna and a feed antenna with a zero-focal lens
Effect of 1-methyl-3-octylimidazolium bromide to the permeability of human skin when applied in different media
No full textUniverzita Karlova, Farmaceutická fakulta v Hradci Králové Katedra Farmaceutické technologie Školitel: Dr. Georgios Paraskevopoulos, Ph.D. Autor: Tereza Stehlíková Název diplomové práce: Vliv aplikace 1-methyl-3-oktylimidazolium bromidu v různých médiích na permeabilitu lidské kůže V této diplomové práci byl zkoumán účinek iontových kapalin (IL) na permeabilitu lidské kůže. IL představují potencionální skupinu látek, které mohou usnadňovat přenos léčiv kůží. V pokusu byla použita amfifilní IL 1-methyl-3- oktylimidazolium bromid (C8MIM). Jako modelové sloučeniny byly využity theofylin (TH), hydrofilní molekula a diklofenak sodný (DIC), více lipofilní a větší molekula. Byla vybrána tři různá média pro aplikaci modelových látek (voda (H2O), 60% propylenglykol (PG) v H2O a ethanol (EtOH) 96%). Připravené vzorky byly využity pro permeační experimenty na lidské kůži. Výsledky ukazují zvýšené pronikání TH lidskou kůží v přítomnosti C8MIM při aplikaci v H2O a EtOH 96%, u 60% PG nikoli. Zadržení TH v kůži bylo významné při použití EtOH 96% (s vysokou variabilitou mezi vzorky) a u ostatních rozpouštědel nebyly výsledky statisticky významné. U vzorků s DIC a C8MIM se v žádném z případů nezvýšilo pronikání kůží (při aplikaci v H2O došlo dokonce ke snížení množství DIC v akceptoru oproti vzorku bez C8MIM)....Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: Dr. Georgios Paraskevopoulos, Ph.D. Author: Tereza Stehlíková Title of the thesis: Effect of 1-methyl-3-octylimidazolium bromide to the permeability of human skin when applied in different media In this thesis, the effect of ionic liquids (IL) on the permeability of human skin was investigated. IL represent a potential group of substances that can facilitate the transfer of drugs through the skin. The amphiphilic IL 1-methyl-3-octylimidazolium bromide (C8MIM) was used in the experiment. Theophylline (TH), a hydrophilic molecule, and diclofenac sodium (DIC), a more lipophilic and larger molecule, were used as model compounds. Three different media were chosen for the application of the model substances (water (H2O), 60% propylene glycol (PG) in H2O and Ethanol (EtOH) 96%). The prepared samples were used for permeation experiments on human skin. The results showed increased penetration of TH through human skin in the presence of C8MIM when applied in H2O and EtOH 96%, but not by 60% PG in H2O. Skin retention of TH was significant using EtOH 96% (with high variability between samples) and results were not statistically significant for the other solvents. Skin penetration did not increase in...Department of Pharmaceutical TechnologyKatedra farmaceutické technologieFarmaceutická fakulta v Hradci KrálovéFaculty of Pharmacy in Hradec Králov
Permeability effect on human skin after pretreatment with selected imidazolium ionic liquids
No full textCharles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: doc. Dr. Georgios Paraskevopoulos Ph.D. Author: Emília Neupauerová Title of the thesis: Permeability effect on human skin after pretreatment with selected imidazolium ionic liquids Ionic Liquids (ILs) are defined as compounds composed of organic or inorganic ions with a melting point lower than of 100 řC. There is promising potential in using ILs as skin permeation enhancers. The permeability effect of 1- methyl-3-octylimidazolium bromide (C8MIM) and 1-dodecyl-3-methylimidazolium bromide (C12MIM) was investigated on human skin. The selected ILs were initially applied on skin tissue and the transepidermal water loss (TEWL) of the treated tissue was measured. In addition, two model permeants (theophylline (TH) and diclofenac sodium (DIC)) were applied on the treated and untreated skin as aqueous suspensions. The amount of the permeants which was absorbed by the skin (topical effect) and went through the skin (transdermal delivery) was evaluated. The results showed that C12MIM and C8MIM pretreated tissues showed statistically significant higher TEWL values when compared with untreated tissue. In addition, statistically significant higher amounts of both model permeants permeated through the..
Effect of 1-methyl-3-octylimidazolium bromide to the permeability of human skin when applied in different media
No full textCharles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: Dr. Georgios Paraskevopoulos, Ph.D. Author: Tereza Stehlíková Title of the thesis: Effect of 1-methyl-3-octylimidazolium bromide to the permeability of human skin when applied in different media In this thesis, the effect of ionic liquids (IL) on the permeability of human skin was investigated. IL represent a potential group of substances that can facilitate the transfer of drugs through the skin. The amphiphilic IL 1-methyl-3-octylimidazolium bromide (C8MIM) was used in the experiment. Theophylline (TH), a hydrophilic molecule, and diclofenac sodium (DIC), a more lipophilic and larger molecule, were used as model compounds. Three different media were chosen for the application of the model substances (water (H2O), 60% propylene glycol (PG) in H2O and Ethanol (EtOH) 96%). The prepared samples were used for permeation experiments on human skin. The results showed increased penetration of TH through human skin in the presence of C8MIM when applied in H2O and EtOH 96%, but not by 60% PG in H2O. Skin retention of TH was significant using EtOH 96% (with high variability between samples) and results were not statistically significant for the other solvents. Skin penetration did not increase in..
Effect of PAMAM dendrimers to the solubility and the skin permeation of diclofenac sodium
No full textUniverzita Karlova, Farmaceutická fakulta v Hradci Králové Katedra Farmaceutické technologie Školitel: doc. Dr. Georgios Paraskevopoulos, Ph.D. Autor: Adéla Lorenčíková Název diplomové práce: Vliv PAMAM dendrimerů na rozpustnost a kožní permeaci diklofenaku sodného Diklofenak sodný (DIC) je léčivá látka patřící do kategorie nesteroidních antiflogistik (NSAID). Tato skupina léčiv je rozsáhle využívána díky pleiotropnímu účinku. Dokáže snižovat horečku, zánět a tišit bolest. Indikační škála je široká. Nevýhodou je však mnoho nežádoucích účinků. Některé z nich lze zmírnit nebo úplně eliminovat jednou z možných cest podání, a to transdermální aplikací. Dále může být ze zmíněných důvodů příznivá lokální aplikace. Jednou z dominantních výzev při snaze dostat léčivou látku přes lidskou kůži nebo do ní je vyhovět kritériím, která jsou kůží definována. Jedná se o vyvážení hydrofilních a lipofilních vlastností. Léčivo musí být schopno penetrovat přes hydrofilní část a zároveň dokázat prostupovat lipofilní lamelární lipidovou multivrstvou, nacházející se v epidermis. Pro zlepšení rozpustnosti DIC ve vodě bylo využito příhodných vlastností poly(amidoaminových) (PAMAM) dendrimerů. PAMAM dendrimery jsou globulární makromolekuly s vysoce organizovanou strukturou. Fungují i jako akceleranty kožní permeace. Tato...Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: doc. Dr. Georgios Paraskevopoulos, Ph.D. Author: Adéla Lorenčíková Title of the thesis: Effect of PAMAM dendrimers to the solubility and the skin permeation of diclofenac sodium Diclofenac sodium (DIC) is a drug belonging to the category of nonsteroidal anti- inflammatory drugs (NSAIDs). This group of drugs is widely used due to its pleiotropic effect. It can reduce fever, inflammation and relieve pain. The range of indications is wide. However, the disadvantage is the many side effects. Some of them can be alleviated or completely eliminated by one of the possible routes of administration, namely transdermal application. Furthermore, local application may be favorable for the aforementioned reasons. One of the dominant challenges in trying to get a drug through or into human skin is to meet the criteria defined by the skin. This is a balance of hydrophilic and lipophilic properties. The drug must be able to penetrate through the hydrophilic part and at the same time be able to penetrate the lipophilic lamellar lipid multilayer found in the epidermis. To improve the solubility of DIC in water, the convenient properties of poly(amidoamine) (PAMAM) dendrimers were used. PAMAM dendrimers are...Department of Pharmaceutical TechnologyKatedra farmaceutické technologieFaculty of Pharmacy in Hradec KrálovéFarmaceutická fakulta v Hradci Králov
2-hydroxyethyl cellulose gels with novel polyamidoamine dendrimers for the skin application of Imiquimod
No full textCharles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: Dr. Georgios Paraskevopoulos, Ph.D. Author: Michaela Prokopová Title of the thesis: 2-hydroxyethyl cellulose gels with novel polyamidoamine dendrimers for the skin application of Imiquimod Imiquimod (IMQ) is a medicinal substance used in the therapy of skin diseases (carcinomas). IMQ's hydrophobicity does not allow its incorporation in hydrophilic gels, which are the most used gel formulations for topical application. Dendritic molecules, which are highly branched polymers, could potentially increase the solubility of IMQ in hydrophilic formulations for the preparation of more concentrated hydrophilic dosage forms. The purpose of this work was to increase the concentration of IMQ in hydrophilic formulations using dendritic molecules. First, aqueous solutions containing IMQ were prepared, in the presence or absence of different generations and concentrations of dendritic molecules. The pH of the solutions was adjusted to 5,5, which corresponds to the pH of the skin. After that, 2-hydroxyethyl cellulose was used as gelling agent to prepare hydrophilic gels as preferable formulations for topical application. Selected solutions and gel formulations, were used for permeation experiments on human...Univerzita Karlova, Farmaceutická fakulta v Hradci Králové Katedra Farmaceutické technologie Školitel: Dr. Georgios Paraskevopoulos, Ph.D. Autor: Michaela Prokopová Název diplomové práce: 2-hydroxyethylcelulózové gely s novými polyamidoaminovými dendrimery pro kožní aplikaci imiquimodu Imiquimod (IMQ) je léčivá látka používaná při léčbě kožních onemocnění (karcinomů). Hydrofobicita IMQ neumožňuje jeho začlenění do hydrofilních gelů, které jsou nejpoužívanějšími gelovými formulacemi pro topickou aplikaci. Dendritické molekuly, které jsou vysoce rozvětvenými polymery, by mohly potenciálně zvýšit rozpustnost IMQ v hydrofilních formulacích pro přípravu koncentrovanějších hydrofilních lékových forem. Účelem této práce bylo zvýšit koncentraci IMQ v hydrofilních formulacích pomocí dendritických molekul. Nejprve byly připraveny vodné roztoky obsahující IMQ v přítomnosti nebo nepřítomnosti různých generací a koncentrací dendritických molekul. pH roztoků bylo upraveno na 5,5, což odpovídá pH pokožky. Poté byla použita 2-hydroxyethylcelulóza jako gelující látka pro přípravu hydrofilních gelů, jako výhodných formulací pro topickou aplikaci. Vybrané roztoky a gelové formulace byly použity pro permeační experimenty na lidské kůži. Výsledky této práce dokazují, že přítomnost dendritických molekul může zvýšit...Katedra farmaceutické technologieDepartment of Pharmaceutical TechnologyFaculty of Pharmacy in Hradec KrálovéFarmaceutická fakulta v Hradci Králov
2-hydroxyethyl cellulose gels with novel polyamidoamine dendrimers for the skin application of Imiquimod
No full textUniverzita Karlova, Farmaceutická fakulta v Hradci Králové Katedra Farmaceutické technologie Školitel: Dr. Georgios Paraskevopoulos, Ph.D. Autor: Michaela Prokopová Název diplomové práce: 2-hydroxyethylcelulózové gely s novými polyamidoaminovými dendrimery pro kožní aplikaci imiquimodu Imiquimod (IMQ) je léčivá látka používaná při léčbě kožních onemocnění (karcinomů). Hydrofobicita IMQ neumožňuje jeho začlenění do hydrofilních gelů, které jsou nejpoužívanějšími gelovými formulacemi pro topickou aplikaci. Dendritické molekuly, které jsou vysoce rozvětvenými polymery, by mohly potenciálně zvýšit rozpustnost IMQ v hydrofilních formulacích pro přípravu koncentrovanějších hydrofilních lékových forem. Účelem této práce bylo zvýšit koncentraci IMQ v hydrofilních formulacích pomocí dendritických molekul. Nejprve byly připraveny vodné roztoky obsahující IMQ v přítomnosti nebo nepřítomnosti různých generací a koncentrací dendritických molekul. pH roztoků bylo upraveno na 5,5, což odpovídá pH pokožky. Poté byla použita 2-hydroxyethylcelulóza jako gelující látka pro přípravu hydrofilních gelů, jako výhodných formulací pro topickou aplikaci. Vybrané roztoky a gelové formulace byly použity pro permeační experimenty na lidské kůži. Výsledky této práce dokazují, že přítomnost dendritických molekul může zvýšit...Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: Dr. Georgios Paraskevopoulos, Ph.D. Author: Michaela Prokopová Title of the thesis: 2-hydroxyethyl cellulose gels with novel polyamidoamine dendrimers for the skin application of Imiquimod Imiquimod (IMQ) is a medicinal substance used in the therapy of skin diseases (carcinomas). IMQ's hydrophobicity does not allow its incorporation in hydrophilic gels, which are the most used gel formulations for topical application. Dendritic molecules, which are highly branched polymers, could potentially increase the solubility of IMQ in hydrophilic formulations for the preparation of more concentrated hydrophilic dosage forms. The purpose of this work was to increase the concentration of IMQ in hydrophilic formulations using dendritic molecules. First, aqueous solutions containing IMQ were prepared, in the presence or absence of different generations and concentrations of dendritic molecules. The pH of the solutions was adjusted to 5,5, which corresponds to the pH of the skin. After that, 2-hydroxyethyl cellulose was used as gelling agent to prepare hydrophilic gels as preferable formulations for topical application. Selected solutions and gel formulations, were used for permeation experiments on human...Department of Pharmaceutical TechnologyKatedra farmaceutické technologieFaculty of Pharmacy in Hradec KrálovéFarmaceutická fakulta v Hradci Králov
The evaluation of the effect of PAMAM dendrimers in the solubility of lmiquimod
No full textCharles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: Dr. Georgios Paraskevopoulos, Ph.D. Consultant: Eleni Panoutsopoulou Author: Mgr. Thu Thao Truongová Title of the thesis: The evaluation of the effect of PAMAM dendrimers in the solubility of Imiquimod Dendrimers are highly branched polymeric compounds with defined properties. They are used as a nanoparticle delivery system, however concurrently they have significant potential in enhancing the solubility of poorly water soluble drugs. Dendrimers work as drug carriers either by encapsulating the drug in their branched internal structure or they create interactions with the drug in the outer layer via terminal functional groups. The aim of this work was to evaluate the effect of polyamidoamine (PAMAM) dendrimers on the solubility of the hydrophobic drug imiquimod. Solutions of zero, first, second and third generation dendrimers were prepared at six different concentrations. During the experiment, the pH of the solutions was measured before and after addition of excess amount of imiquimod. Subsequently, analysis was performed by high-performance liquid chromatography. The measured results show that the first generation of PAMAM dendrimers is able to increase the solubility of imiquimod in..
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