529 research outputs found
Analytical and computational study of curvature depending functionals in image segmentation
No full textIn questa tesi sono stati trattati problemi di segmentazione dell'immagine mediante strumenti di analisi variazionale. Ho studiato due funzionali contenenti integrali di funzioni dipendenti dalla curvatura degli elementi di una famiglia di curve approssimante i contorni di una data immagine, la lunghezza di esse e il numero dei loro punti finali.
Per uno dei due funzionali ho calcolato il sistema delle equazioni di Eulero e, usando uno schema iterativo basato sulle differenze finite, ho effettuato esperimenti al computer su alcune immagini.In the present thesis we study variational problems for image segmentation. We consider two specific classes of functionals which contain
the integral of a function of curvature along the unknown set of curves , the length of such curves and the counting measure of the set of theirs endpoints.
For the second functionals we derive the system of Euler equations, we design an iterative numerical scheme based on finite differences for the solution of the Euler equations,
and we discuss the outcome of some computer experiments on simulated images
PARRILLO V. ITALY - DONATION OF HUMAN EMBRYOS IN VITRO TO SCIENTIFIC RESEARCH
No full textDiplomsko delo obravnava pravno ureditev raziskav na in vitro zarodkih. Temeljna pozornost je posvečena analizi sodbe Evropskega sodišča za človekove pravice v zadevi Parrillo proti Italiji, v kateri je bilo sodišče postavljeno pred vprašanje, ali je italijanska ureditev, ki je pritožnici onemogočila donacijo in vitro zarodkov v znanstvene namene, v skladu z 8. členom Konvencije o varstvu človekovih pravic in temeljnih svoboščin. Pri tem avtor ugotavlja, da imajo države v obravnavanem primeru široko polje proste presoje, saj se področje doniranja in vitro zarodkov v znanstvene namene dotika občutljivih moralnih in etičnih vprašanj, o navedeni problematiki pa tudi ni evropskega konsenza. V zvezi z dopustnostjo raziskav na in vitro zarodkih mora vsaka država postaviti jasne omejitve in pogoje, lahko pa jih tudi prepove. Prikazana je tudi pravna ureditev področja raziskav na in vitro zarodkih, z vidika ureditve na mednarodnopravni ravni, v posameznih državah in v Republiki Sloveniji.The subject of this thesis is a legal regulation of embryos in vitro research. A particular attention is paid to analysis the judgement of the European Court of Human Rights in case of Parrillo v. Italy. The case concerned a ban under Italian Law no. 40/2004, preventing Ms Parrillo from donating to scientific research embryos obtained from an in vitro fertilisation. Ms Parrillo considered that the prohibition in question amounted to a violation of her right to respect for her private life, protected by Article 8 of the Convention for the Protection of Human Rights and Fundamental Freedoms. The author establishes that The Court considered at the outset that European Countries were to be afforded a wide margin of appreciation in this case, which raised sensitive moral and ethical issues, by the lack of a European consensus on the delicate question of the donation of embryos in vitro. Further on, current legal situation in the international law, in some European Countries and in the Republic of Slovenia is presented
The role of activated carbon size in the catalytic cracking of naphthalene
No full textActivated carbons are efficient catalysts for tar cracking, suitable for hot cleaning of the syngas produced during biomass- and waste-to-energy gasification processes. This study investigates the conversion of naphthalene, utilised as reference for tar compounds, when catalysed by a coal-derived activated carbon. The attention focuses on the influence of the operating temperature, in the range 750-900°C, and the size of selected activated carbon, which has been used under form of pellets, granules and powders. The conversion efficiency improves when the temperature raised from 750°C to 900°C (from 79% to 99%, for the pellets), and when the catalyst size reduced from pellets to powders (from 79% to 97%, at 750°C). The diffusional resistance in the catalyst particles has been then quantified in terms of Thiele modulus and internal effectiveness factor. A gradual reduction of catalyst surface area has been also observed for longer tests, due to the progressive deposition of soot from naphthalene decomposition over and inside the porous structure of the activated carbon. The carbon content of these deposits has been quantified, showing larger percentages on the surface of granules and powders.Activated carbons are efficient catalysts for tar cracking, suitable for hot cleaning of the syngas produced during biomass- and waste-to-energy gasification processes. This study investigates the conversion of naphthalene, utilised as reference for tar compounds, when catalysed by a coal-derived activated carbon. The attention focuses on the influence of the operating temperature, in the range 750–900 °C, and the size of selected activated carbon, which has been used under form of pellets, granules and powders. The conversion efficiency improves when the temperature raised from 750 °C to 900 °C (from 79% to 99%, for the pellets), and when the catalyst size reduced from pellets to powders (from 79% to 97%, at 750 °C). The diffusional resistance in the catalyst particles has been then quantified in terms of Thiele modulus and internal effectiveness factor. A gradual reduction of catalyst surface area has been also observed for longer tests, due to the progressive deposition of soot from naphthalene decomposition over and inside the porous structure of the activated carbon. The carbon content of these deposits has been quantified, showing larger percentages on the surface of granules and powders
From lab to daily life: determining the acute neurochemical effects of intrusive thinking in pathological and non-pathological worriers
No full textBackground: Intrusive thinking (IT) is a transdiagnostic psychiatric symptom that causes clinically significant distress and impairments in important areas of functioning. Alterations in glutamate and GABA metabolism are posited to be implicated in the pathophysiology of many neuropsychiatric disorders, such as depression and generalized anxiety disorder[1,2]. However, in humans, levels of such metabolites are quantified ex vivo or in circulating plasma. Moreover, comparisons between pathological and healthy individuals are primarily at rest[3] and not during specific disease states, making it difficult to understand the psychobiological processes underpinning IT.
The present study had two Aims: i) investigating the acute effects of an experimental induction of IT on levels of glutamate and GABA in pathological and non-pathological worriers; ii) testing daily-life validity of the results by ecological momentary assessment (EMA) of IT on the same participants.
Methods: 3T-proton magnetic resonance spectroscopy (MRS) was applied in the bilateral Anterior Cingulate Cortex (ACC) and regional levels of Glx (Glutamate+Glutamine) and GABA were in vivo quantified before and after a well-replicated experimental induction of IT[4]. ACC was selected since it regulates the central autonomic network and it is involved in the clinical maintenance of IT[5]. After completed a psychiatric and clinical screening, both pathological (n = 16; 7 males) and control individuals (n = 17; 8 males) were asked to recall and describe an episode/image that had been recently intruding in their mind over and over without them wanting this to happen. Visual analog scales were administered at four time points to assess manipulation effects on self-reported momentary mood and levels of thoughts intrusiveness, repetitiveness and stuckness. Heart rate and respiration were recorded throughout MRS sessions to assess the physiological concomitants of IT[4]. Laboratory session was followed-up by a two-day EMA aimed at measuring daily-life emergence of IT. Repeated measures ANOVA and random effect regression models were used as methods of analysis.
Results: The two groups did not differ in any of the examined socio-demographic and baseline variables. The induction strongly engendered levels of thoughts intrusiveness, repetitiveness and stuckness in both groups. Results showed a trend toward an increase in regional levels of GABA from pre- to post-induction in both pathological and healthy individuals, though they were not statistically significant. Notably, an opposite pattern emerged for Glx where a statistically significant Time x Goup interaction emerged (for Glx/Water: p = .04, ηp2= .18; for Glx/Cre: p=.03, ηp2= .17), with a pre- to post-induction increase in controls (ps < .05) and a decrease in pathological worriers (ps < .05). Resting levels of GABA and Glx in ACC predicted subjective responses to the induction (ps < .05) as well as daily life levels of thoughts intrusiveness and repetitiveness (ps < .05).
Conclusion: Current findings suggest that dysfunctions in glutamatergic neurometabolism within ACC may contribute to the maintenance of IT in pathological individuals, and they are in line with a dimensional view of psychopathology, showing that IT has the effect of making healthy individuals neurally-like disordered ones. If replicated, present results may inform personally-tailored treatments in the framework of precision psychiatry.
References
[1] Brambilla P, Perez J, Barale F, Schettini G, Soares JC. GABAergic dysfunction in mood disorders. Mol Psychiatry. 2003;8(8):721-737. [2] Lener MS, Niciu MJ, Ballard ED, et al. Glutamate and Gamma-Aminobutyric Acid Systems in the Pathophysiology of Major Depression and Antidepressant Response to Ketamine. Biological Psychiatry. 2017;81(10):886-897. [3] Moriguchi S, Takamiya A, Noda Y, et al. Glutamatergic neurometabolite levels in major depressive disorder: a systematic review and meta-analysis of proton magnetic resonance spectroscopy studies. Mol Psychiatry. 2019;24(7):952-964. [4] Ottaviani C, Thayer JF, Verkuil B, et al. Physiological concomitants of perseverative cognition: A systematic review and meta-analysis. Psychological Bulletin. 2016;2016;142(3):231-25959. [5] Makovac E, Fagioli S, Rae CL, Critchley HD, Ottaviani C. Can’t get it off my brain: Meta-analysis of neuroimaging studies on perseverative cognition. Psychiatry Research: Neuroimaging. 2020;295:111020
Waste-derived catalysts for tar cracking in hot syngas cleaning
No full text: Catalytic tar cracking is a promising technique for hot syngas cleaning unit in gasification plants because it can preserve tars chemical energy, so increasing the syngas heating value. The cost associated with catalyst preparation is a key issue, together with its deactivation induced by coke deposition. Iron is a cheap and frequently used catalyst, which can also be found in some industrial wastes. The study aims to assess the catalytic efficiency for tar cracking of two waste-derived materials (red mud and sewage sludge) having high content of iron. The catalysts were supported on spheres of γ-Al2O3, and their efficiency was compared to that of a pure iron catalyst. The role of support was investigated by testing pure red mud, with and without the support. A series of long-term tests using naphthalene as tar model compound were carried out under different values of process temperatures (750 °C-800 °C) and steam concentrations (0 %-7.5 %). The waste derived catalysts showed lower hydrogen yields compared to pure iron catalyst, due to their lower content of iron. On the other hand, the conversion efficiencies of all the tested catalysts resulted rather similar, since the Alkali and Alkaline-Earth Metallic species present on the surface of waste-derived catalyst help in preventing coke deposition. The iron oxidation state appears to play an important role, with reduced iron more active than its oxidised form in the tar cracking reactions. This indicates the importance of tuning steam concentration to keep constant the reduced state of iron while limiting coke deposition
Effects of short- and long-term fasting on the ovarian axis and reproductive performance on rabbit does.
No full textPersonalized Medicine and Type 2 Diabetes: Lesson from Epigenetics
No full textSimilarly to genetic polymorphisms, epigenetic modifications may alter transcriptional activity and contribute to different traits of the Type 2 diabetes phenotype. The establishment of these epigenetic marks may precede diabetes onset and predict the disease. Current evidence now indicates that epigenetic differences represent markers of diabetes risk. Studies on epigenome plasticity revealed that cytokines and other metabolites, by affecting DNA methylation, may acutely reprogram gene expression and contribute to the Type 2 diabetes phenotype even in the adult life. The available evidence further indicates that epigenetic marks across the genome are subject to dynamic variations in response to environmental cues. Finally, different genes responsible for the interindividual variability in antidiabetic drug response are subjected to epigenetic regulation. Determining how specific epigenetic profiles determine diabetes is a challenging task. In the near future, the identification of epigenetic marks predictive of diabetes risk or response to treatment may offer unanticipated opportunities to personalize Type 2 diabetes management
Obtención de whiskers de nitruro de silicio y oxinitruro de silicio a partir de cáscara de arroz y ceniza de cáscara de arroz
No full textLa cáscara de arroz constituye el principal subproducto asociado a la industrialización del arroz, un alimento cuya demanda global crece día a día. En la actualidad no se cuenta, ni en el país ni a nivel mundial, con un destino final sostenible para disponer de las grandes cantidades de cáscara de arroz generadas, lo cual representa un serio pasivo ambiental. La generación de energía a partir de esta biomasa sufre de un pasivo similar, ya que tampoco se dispone de un destino final adecuado para la ceniza resultante de la combustión. Por ende, el empleo de cáscara de arroz y ceniza de cáscara de arroz como materiales de partida para la obtención de productos de mayor valor permite alcanzar un doble propósito ambiental y económico. En particular, la presencia de sílice y carbono en íntimo contacto, tanto en la cáscara de arroz como en la ceniza de cáscara de arroz, convierte a estos materiales en precursores atractivos para procesos que impliquen una reducción carbotérmica.
En este trabajo se analizó la factibilidad de varios diseños experimentales para producir, mediante reducción carbotérmica y nitruración, whiskers de nitruro u oxinitruro de silicio utilizando como precursores cáscara de arroz nacional y ceniza de cáscara de arroz proveniente de un emprendimiento nacional de cogeneración. La fuente de carbono necesaria para reaccionar con la sílice presente en los materiales de partida fue provista por la materia orgánica presente en los mismos, sin agregado de otros reactivos carbonáceos. Se consideró el uso de cáscara de arroz y ceniza de cáscara de arroz tal cual son obtenidas con el fin de desarrollar un proceso sencillo y fácilmente adaptable a las necesidades industriales. Se ensayó también un pretratamiento de la ceniza de cáscara de arroz con el objetivo conjunto de obtener un material de partida más propicio para la reducción carbotérmica y nitruración, y, a la vez, sílice precipitada como subproducto de interés. Dicho proceso consistió en un método sencillo de digestión alcalina de la ceniza seguida de filtrado y precipitación ácida de la sílice solubilizada. Las condiciones requeridas para remover la cantidad de sílice deseada de la ceniza de cáscara de arroz fueron determinadas experimentalmente. Para el proceso de reducción carbotérmica y nitruración, el material de partida pertinente fue introducido en crisoles con tapa y sometido a tratamiento térmico bajo atmósfera de nitrógeno, analizándose diferentes temperaturas de meseta y varias configuraciones que permitieron evaluar la importancia de la presencia de superficies de grafito en el proceso. Se logró obtener whiskers de nitruro de silicio y oxinitruro de silicio bajo diferentes condiciones. Mientras
que los whiskers de nitruro de silicio presentaron secciones de entre aproximadamente 100 nm hasta 1 μm,
los whiskers de oxinitruro de silicio contaron con secciones de entre aproximadamente 100 nm hasta 500 nm.
El largo de ambas clases de whiskers se encontró en el rango de los milímetros. En la mayoría de los casos, los
whiskers obtenidos pudieron ser sencillamente recuperados. La temperatura de meseta del tratamiento
térmico presentó un efecto relevante sobre el proceso, obteniéndose los mejores resultados para la
temperatura más elevada ensayada, 1400°C. La presencia de superficies de grafito en el medio de reacción
resultó significativa. El pretratamiento impuesto sobre la ceniza de cáscara de arroz permitió ajustar la relación
carbono a sílice al valor deseado, generando una mejora significativa en los resultados de reducción
carbotérmica y nitruración, y posibilitando la obtención simultánea de sílice precipitada.Rice is a food commodity in continuously increasing demand, with rice husk being the main by-product of
rice industrialization. The lack of a sustainable destination for the large amounts of rice husk produced, both
locally and globally, constitutes a serious environmental liability. Burning the husk for energy purposes poses
a similar issue since the ashes produced in the process do not have a proper use either. As a result, using rice
husk and rice husk ash as starting materials to manufacture higher-value products fulfills not only an
environmental but also an economical purpose. Particularly, the presence of silica and carbon in intimate
contact in both rice husk and rice husk ash makes these materials attractive precursors for carbothermal
reduction processes.
In this work, rice husk from a national provider and rice husk ash coming from a local cogeneration plant
were assessed as starting materials in different experimental setups for silicon nitride or oxynitride whiskers
production through carbothermal reduction and nitridation. The organic matter already in rice husk and rice
husk ash provided the carbon source required to react with the silica in the starting materials, so no carbon-
based reagents were added. In order to develop a non-complex process that could be easily applied to
industrial needs, the use of as-received rice husk and rice husk ash was assessed. However, aiming to render
not only a more appropriate starting material for the carbothermal reduction and nitridation process, but also
precipitated silica as a by-product, a pre-treatment of the ash was also developed and analyzed. This process
involved a simple alkaline digestion step followed by filtering and acid precipitation of the solubilized silica.
The conditions that allowed for the removal of the desired amount of silica from the rice husk ash were
determined experimentally. For carbothermal reduction and nitridation, the proper material was introduced
in crucibles with lids and heat treated under nitrogen atmosphere. Different soaking temperatures were
evaluated, along with several experimental setups that allowed for the assessment of the significance of
graphite surfaces on the process.
Silicon nitride and oxynitride whiskers were obtained under different conditions. Silicon nitride whiskers'
widths varied from 100 nm up to 1 μm approximately, whereas the silicon oxynitride whiskers were between
roughly 100 nm and 500 nm wide. Both types of whiskers were in the millimeter range. In most cases the
whiskers produced could be easily recovered. The soaking temperature had a significant impact on the
process, and 1400°C, the highest temperature evaluated, produced the best results. The presence of graphite surfaces in the reaction chamber proved to be noteworthy. The pretreatment of the rice husk ash developed
enabled the adjustment of the carbon to silica ratio, producing a substantial improvement in the carbothermal
reduction and nitridation results, and enabling the simultaneous obtention of precipitated silica
1-Acyl-, 3-acyl- and 1,3-diacyl-3-furfuryl-1-phenylthioureas with platelet antiaggregating and other activities.
No full textThe synthesis in excellent yields of 1-acyl-3-furfuryl-1-phenylthioureas (I) (R - aryl) by reacting at t ≤ 10° 3-furfuryl-1-phenylthiourea (II), prepd. in situ from furfurylamine and Ph isothiocyanate, with arom. or heterocyclic acyl chlorides in pyridine soln. is described. The 1-acylthioureas I rearranged in high yields to 3-acylthioureas (III) (R = aryl) by treatment with sodium hydroxide in heterogeneous phase. The 1,3-diacyl-3-furfuryl-1-phenylthioureas (IV) (R = aryl C) were obtained in satisfactory yields by treatment of II with 2 mol of acyl chloride as in the case of 1-monoacylation. The thiourea II prepd. in situ reacted with iodomethane in DMF soln. and in the presence of sodium hydride to give in high yield the S-Me deriv., namely the Me ester of N-phenyl-1-furfurylaminethiocarboximidic acid. Some acylthioureas I and IV showed a platelet antiaggregating activity in vitro superior or comparable to that of acetylsalicylic acid. The 1,3-diacylthiourea IV (R = 4-MeOC6H4) exhibited an appreciable anticonvulsant activity in mice, some compds. (I and IV) showed moderate competitive antiacetylcholine and H1-antihistamine effects in vitro
Severe paraneoplastic hypercalcemia secondary to an oral melanoma and palliative treatment with zoledronic acid in a dog
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