Perdite aeree prolungate dopo resezione polmonare

Il tumore del polmone e una delle neoplasie più diagnosticate dal 1985 e rimane ancora oggi la causa più frequente di morte cancro-correlata nel mondo. Una resezione polmonare anatomica completa continua ad essere il cardine della terapia per il tumore non a piccole cellule. Perdite aeree prolungate (PAL) sono la più comune complicanza dopo una chirurgia polmonare e sono state riportate con un’incidenza compresa tra il 3-26%, simile sia nelle resezioni polmonari per via toracotomica sia in quelle per via toracoscopica. Fattori di rischio descritti sono scissure interlobari incomplete, patologie polmonari sottostanti (come enfisema, fibrosi, tubercolosi o neoplasie), aderenze pleuriche, pazienti anziani (>75 anni) e bassa capacita di diffusione. Lo sviluppo di strumentazione all’avanguardia e di nuove tecniche chirurgiche ha contribuito a ridurre l’incidenza di queste complicanze. Considerando l’alto impatto clinico e socio-economico di queste problematiche, e stata inoltre sviluppata una varietà di complementari naturali e materiali sintetici molti utili nella gestione delle perdite aeree.

Vitellogenin synthesis in primary cultures of fish liver cells as endpoint for in vitro screening of the (anti)estrogenic activity of chemical substances

Concern over possible adverse effects of endocrine-disrupting compounds on fish has caused the development of appropriate testing methods. In vitro screening assays may provide initial information on endocrine activities of a test compound and thereby may direct and optimize subsequent testing. Induction of vitellogenin (VTG) is used as a biomarker of exposure of fish to estrogen-active substances. Since VTG induction can be measured not only in vivo but also in fish hepatocytes in vitro, the use of VTG induction response in isolated fish liver cells has been suggested as in vitro screen for identifying estrogenic-active substances. The main advantages of the hepatocyte VTG assay are considered its ability to detect effects of estrogenic metabolites, since hepatocytes in vitro remain metabolically competent, and its ability to detect both estrogenic and anti-estrogenic effects. In this article, we critically review the current knowledge on the VTG response of cultured fish hepatocytes to (anti)estrogenic substances. In particular, we discuss the sensitivity, specificity, and variability of the VTG hepatocyte assay. In addition, we review the available data on culture factors influencing basal and induced VTG production, the response to natural and synthetic estrogens as well as to xenoestrogens, the detection of indirect estrogens, and the sources of assay variability. The VTG induction in cultured fish hepatocytes is clearly influenced by culture conditions (medium composition, temperature, etc.) and culture system (hepatocyte monolayers, aggregates, liver slices, etc.). The currently available database on estrogen-mediated VTG induction in cultured teleost hepatocytes is too small to support conclusive statements on whether there exist systematic differences of the VTG response between in vitro culture systems, VTG analytical methods or fish species. The VTG hepatocyte assay detects sensitively natural and synthetic estrogens, whereas the response to xenoestrogens appears to be more variable. The detection of weak estrogens can be critical due to the overshadow with cytotoxic concentrations. Moreover, the VTG hepatocyte assay is able to detect antiestrogens as well as indirect estrogens, i.e substances which require metabolic activation to induce an estrogenic response. Nevertheless, more chemicals need to be analysed to corroborate this statement. It will be necessary to establish standardized protocols to minimize assay variability, and to develop a set of pass-fail criteria as well as cut-offs for designating positive and negative responses.

Eluding antibiotic resistance: capitalizing on antimicrobial peptides interaction with the lipid bilayer

It is widely accepted that the emergence of drug-resistant pathogens is the result of the overuse and misuse of antibiotics. Infectious Disease Society of America, Center for Disease Control and World Health Organization continue to view, with concern, the lack of antibiotics in development, especially those against Gram-negative bacteria. Antimicrobial peptides (AMPs) have been proposed as an alternative to antibiotics due to their selective activity against microbes and minor ability to induce resistance. For example, the Food and Drug Administration approved Daptomycin (DAP) in 2003 for treatment of severe skin infections caused by susceptible Gram-positive organisms. Currently, there are 12 to 15 examples of modified natural and synthetic AMPs in clinical development. But most of these agents are against Gram-positive bacteria. Therefore, there is unmet medical need for antimicrobials used to treat infections caused by Gram-negative bacteria. In this study, we show that a pro-apoptotic peptide predominantly used in cancer therapy, (KLAKLAK)2, is an effective antimicrobial against Gram-negative laboratory strains and clinical isolates. Despite the therapeutic promise, AMPs development is hindered by their susceptibility to proteolysis. Here, we demonstrate that an all-D enantiomer of (KLAKLAK)2, resistant to proteolysis, retains its activity against Gram-negative pathogens. In addition, we have elucidated the specific site and mechanism of action of D(KLAKLAK)2 through a repertoire of whole-cell and membrane-model assays. Although it is considered that development of resistance does not represent an obstacle for AMPs clinical development, strains with decreased susceptibility to these compounds have been reported. Staphylococci resistance to DAP was observed soon after its approval for use and has been linked to alterations of the cell wall (CW) and cellular membrane (CM) properties. Immediately following staphylococcal resistance, Enterococci resistance to DAP was seen, yet the mechanism of resistance in enterococci remains unknown. Our findings demonstrate that, similar to S. aureus, development of DAP-resistance in a vancomycin-resistant E. faecalis isolate is associated with alterations of the CW and properties of the CM. However, the genes linked to these changes in enterococci appear to be different from those described in S. aureus.

Spectral Biomimetic Technique for Wood Classification

Palatal clicks are most interesting for human echolocation. Moreover, these sounds are suitable for other acoustic applications due to their regular mathematical properties and reproducibility. Simple and nondestructive techniques, bioinspired by synthetized pulses whose form reproduces the best features of palatal clicks, can be developed. The use of synthetic palatal pulses also allows detailed studies of the real possibilities of acoustic human echolocation without the problems associated with subjective individual differences. These techniques are being applied to the study of wood. As an example, a comparison of the performance of both natural and synthetic human echolocation to identify three different species of wood is presented. The results show that human echolocation has a vast potential.

Ionization energies of amphoteric-doped Cu2ZnSnS4: Photovoltaic application

The substitution of Cu, Sn or Zn in the quaternary Cu2ZnSnS4 semiconductor by impurities that introduce intermediate states in the energy bandgap could have important implications either for photovoltaic or spintronic applications. This allows more generation–recombination channels than for the host semiconductor. We explore and discuss this possibility by obtaining the ionization energies from total energy first-principles calculations. The three substitutions of Cu, Sn and Zn by impurities are analyzed. From these results we have found that several impurities have an amphoteric behavior with the donor and acceptor energies in the energy bandgap. In order to analyze the role of the ionization energies in both the radiative and non-radiative processes, the host energy bandgap and the acceptor and the donor energies have been obtained as a function of the inward and outward impurity-S displacements. We carried out the analysis for both the natural and synthetic CZTS. The results show that the ionization energies are similar, whereas the energy band gaps are different.

Utilización de modelos hidráulicos bidimensionales en la determinación del tiempo de concentración

El tiempo de concentración de una cuenca sigue siendo relativamente desconocido para los ingenieros. El procedimiento habitual en un estudio hidrológico es calcularlo según varias fórmulas escogidas entre las existentes para después emplear el valor medio obtenido. De esta media se derivan los demás resultados hidrológicos, resultados que influirán en el futuro dimensionamiento de las infraestructuras. Este trabajo de investigación comenzó con el deseo de conseguir un método más fiable y objetivo que permitiera obtener el tiempo de concentración. Dada la imposibilidad de poner en práctica ensayos hidrológicos en una cuenca física real, ya que no resulta viable monitorizar perfectamente la precipitación ni los caudales de salida, se planteó llevar a cabo los ensayos de forma simulada, con el empleo de modelos hidráulicos bidimensionales de lluvia directa sobre malla 2D de volúmenes finitos. De entre todos los disponibles, se escogió InfoWorks ICM, por su rapidez y facilidad de uso. En una primera fase se efectuó la validación del modelo hidráulico elegido, contrastando los resultados de varias simulaciones con la formulación analítica existente. Posteriormente, se comprobaron los valores de los tiempos de concentración obtenidos con las expresiones referenciadas en la bibliografía, consiguiéndose resultados muy satisfactorios. Una vez verificado, se ejecutaron 690 simulaciones de cuencas tanto naturales como sintéticas, incorporando variaciones de área, pendiente, rugosidad, intensidad y duración de las precipitaciones, a fin de obtener sus tiempos de concentración y retardo. Esta labor se realizó con ayuda de la aceleración del cálculo vectorial que ofrece la tecnología CUDA (Arquitectura Unificada de Dispositivos de Cálculo). Basándose en el análisis dimensional, se agruparon los resultados del tiempo de concentración en monomios adimensionales. Utilizando regresión lineal múltiple, se obtuvo una nueva formulación para el tiempo de concentración. La nueva expresión se contrastó con las formulaciones clásicas, habiéndose obtenido resultados equivalentes. Con la exposición de esta nueva metodología se pretende ayudar al ingeniero en la realización de estudios hidrológicos. Primero porque proporciona datos de manera sencilla y objetiva que se pueden emplear en modelos globales como HEC-HMS. Y segundo porque en sí misma se ha comprobado como una alternativa realmente válida a la metodología hidrológica habitual. Time of concentration remains still fairly imprecise to engineers. A normal hydrological study goes through several formulae, obtaining concentration time as the median value. Most of the remaining hydrologic results will be derived from this value. Those results will determine how future infrastructures will be designed. This research began with the aim to acquire a more reliable and objective method to estimate concentration times. Given the impossibility of carrying out hydrological tests in a real watershed, due to the difficulties related to accurate monitoring of rainfall and derived outflows, a model-based approach was proposed using bidimensional hydraulic simulations of direct rainfall over a 2D finite-volume mesh. Amongst all of the available software packages, InfoWorks ICM was chosen for its speed and ease of use. As a preliminary phase, the selected hydraulic model was validated, checking the outcomes of several simulations over existing analytical formulae. Next, concentration time values were compared to those resulting from expressions referenced in the technical literature. They proved highly satisfactory. Once the model was properly verified, 690 simulations of both natural and synthetic basins were performed, incorporating variations of area, slope, roughness, intensity and duration of rainfall, in order to obtain their concentration and lag times. This job was carried out in a reasonable time lapse with the aid of the parallel computing platform technology CUDA (Compute Unified Device Architecture). Performing dimensional analysis, concentration time results were isolated in dimensionless monomials. Afterwards, a new formulation for the time of concentration was obtained using multiple linear regression. This new expression was checked against classical formulations, obtaining equivalent results. The publication of this new methodology intends to further assist the engineer while carrying out hydrological studies. It is effective to provide global parameters that will feed global models as HEC-HMS on a simple and objective way. It has also been proven as a solid alternative to usual hydrology methodology.

Feedback-inducible nuclear-receptor-driven reporter gene expression in transgenic mice

Understanding nuclear receptor signaling in vivo would be facilitated by an efficient methodology to determine where a nuclear receptor is active. Herein, we present a feedback-inducible expression system in transgenic mice to detect activated nuclear receptor effector proteins by using an inducible reporter gene. With this approach, reporter gene induction is not limited to a particular tissue, and, thus, this approach provides the opportunity for whole-animal screens. Furthermore, the effector and reporter genes are combined to generate a single strain of transgenic mice, which enables direct and rapid analysis of the offspring. The system was applied to localize sites where the retinoic acid receptor ligand-binding domain is activated in vivo. The results identify previously discovered sources of retinoids in the embryo and indicate the existence of previously undiscovered regions of retinoic acid receptor signaling in vivo. Notably, the feedback-inducible nuclear-receptor-driven assay, combined with an independent in vitro assay, provides evidence for a site of retinoid synthesis in the isthmic mesenchyme. These data illustrate the potential of feedback-inducible nuclear-receptor-driven analyses for assessing in vivo activation patterns of nuclear receptors and for analyzing pharmacological properties of natural and synthetic ligands of potential therapeutic value.

Flavonoids Promote Haustoria Formation in the Root Parasite Triphysaria versicolor1

Parasitic plants in the Scrophulariaceae develop infective root structures called haustoria in response to chemical signals released from host-plant roots. This study used a simple in vitro assay to characterize natural and synthetic molecules that induce haustoria in the facultative parasite Triphysaria versicolor. Several phenolic acids, flavonoids, and the quinone 2,6-dimethoxy-p-benzoquinone induced haustoria in T. versicolor root tips within hours after treatment. The concentration at which different molecules were active varied widely, the most active being 2,6-dimethoxy-p-benzoquinone and the anthocyanidin peonidin. Maize (Zea mays) seeds are rich sources of molecules that induce T. versicolor haustoria in vitro, and chromatographic analyses indicated that the active molecules present in maize-seed rinses include anthocyanins, other flavonoids, and simple phenolics. The presence of different classes of inducing molecules in seed rinses was substantiated by the observation that maize kernels deficient in chalcone synthase, a key enzyme in flavonoid biosynthesis, released haustoria-inducing molecules, although at reduced levels compared with wild-type kernels. We discuss these results in light of existing models for host perception in the related parasitic plant Striga.

Novel retinoic acid receptor ligands in Xenopus embryos.

Retinoids are a large family of natural and synthetic compounds related to vitamin A that have pleiotropic effects on body physiology, reproduction, immunity, and embryonic development. The diverse activities of retinoids are primarily mediated by two families of nuclear retinoic acid receptors, the RARs and RXRs. Retinoic acids are thought to be the only natural ligands for these receptors and are widely assumed to be the active principle of vitamin A. However, during an unbiased, bioactivity-guided fractionation of Xenopus embryos, we were unable to detect significant levels of all-trans or 9-cis retinoic acids. Instead, we found that the major bioactive retinoid in the Xenopus egg and early embryo is 4-oxoretinaldehyde, which is capable of binding to and transactivating RARs. In addition to its inherent activity, 4-oxoretinaldehyde appears to be a metabolic precursor of two other RAR ligands, 4-oxoretinoic acid and 4-oxoretinol. The remarkable increase in activity of retinaldehyde and retinol as a consequence of 4-oxo derivatization suggests that this metabolic step could serve a critical regulatory function during embryogenesis.

Redirecting the specificity of ubiquitination by modifying ubiquitin-conjugating enzymes.

Depletion of specific cellular proteins is a powerful tool in biological research and has many medical and agricultural benefits. In contrast to genetic methods currently available to attenuate protein levels, we describe an alternative approach that redirects the ubiquitin-dependent proteolytic pathway to facilitate specific proteolytic removal. Degradation via the ubiquitin pathway requires the prior attachment of multiple ubiquitins to the target protein. This attachment is accomplished, in part, by a family of enzymes designated E2s (or ubiquitin-conjugating enzymes), some of which use domains near their C termini for target recognition. Here, we demonstrate that E2 target recognition can be redefined by engineering E2s to contain appropriate protein-binding peptides fused to their C termini. In five dissimilar examples, chimeric E2s were created that recognized and ubiquitinated their respective binding partners with high specificity. We also show that ubiquitination of one protein targeted by this method led to its ATP-dependent degradation in vitro. Thus, by exploiting interacting domains derived from natural and synthetic ligands, it may be possible to design E2s capable of directing the selective removal of many intracellular proteins.

Interlamellar modification of smectite clays

Clay minerals, both natural and synthetic, have a wide range of applications. Smectite clays are not true insulators, their slight conductivity has been utilized by the paper industry in the development of mildly conducting paper. In particular, the synthetic hectorite clay, laponite, is employed to produce paper which is used in automated drawing offices where electro graphic printing is common. The primary objective of this thesis was to modify smectite clays, particularly laponite, to achieve enhanced conductivity. The primary objective was more readily achieved if the subsidiary objective of understanding the mechanism of conductivity was defined. The cyclic voltammograms of some cobalt complexes were studied in free solution and as clay modified electrodes to investigate the origin of electroactivity in clay modified electrodes. The electroactivity of clay modified electrodes prepared using our method can be attributed to ion pairs sorbed to the surface of the electrode, in excess of the cationic exchange capacity. However, some new observations were made concerning the co-ordination chemistry of the tri-2-pyridylamine complexes used which needed clarification. The a.c. conductivity of pressed discs of laponite RD was studied over the frequency range 12Hz- 100kHz using three electrode systems namely silver-loaded epoxy resin (paste), stainless-steel and aluminium. The a. c. conductivity of laponite consists of two components, reactive (minor) and ionic (major) which can be observed almost independently by utilizing the different electrode systems. When the temperature is increased the conductivity of laponite increases and the activation energy for conductivity can be calculated. Measurement of the conductivity of thin films of laponite RD in two crystal planes shows a degree of anisotropy in the a.c. conductivity. Powder X-ray diffraction and 119Sn Mossbauer spectroscopy studies have shown that attempts to intercalate some phenyltin compounds into laponite RD under ambient conditions result in the formation of tin(IV) oxide pillars. 119Sn Mossbauer data indicate that the order of effectiveness of conversion to pillars is in the order: Ph3SnCl > (Ph3Sn)2O, Ph2SnCl2 The organic product of the pillaring process was identified by 13C m.a.s.n.m.r. spectroscopy as trapped in the pillared lattice. This pillaring reaction is much more rapid when carried out in Teflon containers in a simple domestic microwave oven. These pillared clays are novel materials since the pillaring is achieved via neutral precursors rather than sacrificial reaction of the exchangeable cation. The pillaring reaction depends on electrophilic attack on the aryl tin bond by Brønsted acid sites within the clay. Two methods of interlamellar modification were identified which lead to enhanced conductivity of laponite, namely ion exchange and tin(IV) oxide pillaring. A monoionic potassium exchanged laponite shows a four fold increase in a.c. conductivity compared to sodium exchanged laponite RD. The increased conductivity is due to the appearence of an ionic component. The conductivity is independent of relative humidity and increases with temperature. Tin(IV) oxide pillared laponite RD samples show a significant increase in conductivity. Samples prepared from Ph2SnCl2 show an increase in excess of an order of magnitude. The conductivity of tin(IV) oxide pillared laponite samples is dominated by an ionic component.

Physicochemical properties of hydrogels for use in ophthalmology

This chapter deals with the physicochemical aspects of structure-property relationships in synthetic hydrogels, with particular reference to their application in optometry and ophthalmology. It demonstrates the ways in which the amount of water contained in the hydrogel network can be manipulated by changes in copolymer composition and illustrates the advantages and limitations imposed by use of water as a means of influencing surface, transport and mechanical properties of the gel. The chapter then illustrates how this basic understanding has formed a platform for the development of synthetic interpenetrating networks and macroporous materials, and of hybrids of natural and synthetic hydrogels. The behaviour of these more complex systems is not so centrally dominated by the equilibrium water content as is the case with homogeneous synthetic hydrogels, thus providing advantageous ways of extending the properties and applications of these interesting materials.

Analyse simultanée des hormones stéroïdiennes et leurs formes chimiques dans les matrices d'eau et d'urine par SPE-LC-MS/MS en ligne.

Dans les dernières années, les perturbateurs endocriniens ont été observés dans les rivières qui reçoivent des entrées importantes d’eaux usées. Parmi les perturbateurs endocriniens, les hormones stéroïdiennes naturelles et synthétiques sont des composés dont le potentiel d'imiter ou d'interférer avec les fonctions hormonales normales (développement, croissance et reproduction), est reconnu même au niveau ultra-traces (ng L-1). Bien que les hormones conjuguées soient moins actives que les hormones libres, elles peuvent être clivées et redevenir libres une fois exposées aux processus microbiens avant ou pendant le traitement des eaux usées. En raison de la nécessité d'identifier et de quantifier ces composés dans l'eau, une nouvelle méthode, entièrement automatisée, a été développée pour la détermination simultanée des deux formes de plusieurs hormones stéroïdiennes (conjuguées et libres) dans les matrices d'eau et dans l’urine des femmes. La méthode est basée sur l'extraction en phase solide couplée en ligne à la chromatographie liquide et la spectrométrie de masse en tandem (SPE-LC-MS/MS). Plusieurs paramètres ont été évalués dans le but d'optimiser l'efficacité de la méthode, tels que le type et le débit de la phase mobile, des différentes colonnes de SPE et de chromatographie, ainsi que différentes sources et modes d'ionisation des échantillons pour la MS. La méthode démontre une bonne linéarité (R2 > 0.993), ainsi qu'une précision avec un coefficient de variance inférieure à 10%. Les limites de quantification varient d’un minimum de 3 à 15 ng L-1 pour un volume d'injection entre 1 mL et 5 mL et le recouvrement des composés varie de 72 % à 117 %.

Thermal degradation studies on Edible Oil during Deep Fat Frying Process

Deep fat frying process is one of the widely followed cooking practices throughout the world. Cooking oils serve as a medium for frying food for transferring heat and makes fried food tasty and palatable. Frying process is a most complex process involving numerous physicochemical changes which are complicated to understand. Frying leads to thermal degradation of oil through thermo-oxidation, hydrolysis, and polymerization. Hydrolysis results in formation of free fatty acids whereas oxidation process produces hydroperoxides and small molecular carbonyl compounds. This whole process leads to the formation of polar compounds and degradation of antioxidants that further degrades frying oil. Eventually, through mass transfer process these degradation products accumulate into fried food and reduce the nutritional quality of both oil and food. Thus, the frying process is of research interest calls for detailed systematic study which is chosen for the present study. The primary objective of this study is to understand the mechanism of degradation and characterization ofdegraded products which helps in arriving at the limits for frying oil utilization in terms of number of frying cycles. The mechanistic studies and the knowledge on the degraded products help to understand the way to retard the deterioration of oil for stability and enhancement of frying cycles. The study also explores the formation of the predominant polar compounds and their structural elucidation through mass spectrometry. Oxidation of oil is another important factor that ignites the degradation phenomena. One of the best ways to increase thermal stability of any oil is addition of potent antioxidants. But, most of the natural and synthetic antioxidants are unstable and ineffective at frying temperatures. Therefore, it is necessary to screen alternative antioxidants for their activity in the refined oils which are devoid of any added antioxidants. In this context, this study discussed the efficacy of several natural and synthetic antioxidants to retard the formation of polar compounds and thermooxidation during prolonged frying conditions. Similarly, the advantage of blending of two different oils to improve the thermal stability was explored. The present study brings out the total picture on the type of degradation products formed during frying and the ways of retarding the determination to improve upon the stability of the oil and enhancement of frying cycles.

Sex steroid feedback regulation of pituitary gonadotropins during early secondary oocyte growth in coho salmon (Oncorhynchus kisutch) – a potential target of endocrine disruption.

Thesis (Ph.D.)--University of Washington, 2016-06