15 research outputs found
LWT based encrypted payload steganography
No full textSteganography is used in covert communication for transportation of secrete information. In this paper we propose LWT based Encrypted Payload Steganography (LEPS). The payload is segmented into two parts say block 1 and block 2. The LWT is applied on block 2 to generate four sub bands. Payload block 1 is retained in the spatial domain itself. The values of approximation band coefficients of block 2 and spatial domain intensity values of block 1 are compressed. The LWT is applied on cover image to generate wavelet sub bands and considered only diagonal sub bands (XD). The XD band is decomposed into three parts. The key values are embedded into first part of XD band. The compressed payload is embedded in second and third blocks of XD adaptively. The payload can be retrieved at the destination by adapting reverse process of embedding. It is observed that the values of PSNR and capacity are better in the case of proposed algorithm compared to existing algorithm
Multilevel Wavelet Fusion Steganography
No full textSteganography is employed in the field of secure communications by embedding secret data in a cover object. In this paper Multilevel Wavelet Fusion Steganography (MWFS) is proposed. The cover-escrow algorithm is used based on the principles of Multilevel Wavelet Fusion, wherein the wavelet coefficients of both the cover and secret images are merged into a single fused image using embedding strength factors alpha and beta. Preprocessing on the cover image and payload are performed to reduce the pixel range in order to ensure that the embedded message is recovered with acceptable accuracy. An experimental result shows high imperceptibility along with improved embedding capacity and high security
Detecting original image using histogram, DFT and SVM
No full textInformation hiding for covert communication is rapidly
gaining momentum. With sophisticated techniques being
developed in steganography, steganalysis needs to be
universal. In this paper we propose Universal Steganalysis
using Histogram, Discrete Fourier Transform and SVM
(SHDFT). The stego image has irregular statistical
characteristics as compare to cover image. Using Histogram
and DFT, the statistical features are generated to train OneClass SVM to discriminate the cover and stego image.
SHDFT algorithm is found to be efficient and fast since the
number of statistical features is less compared to the
existing algorith
EFFECT OF SEASON ON REPRODUCTIVE PERFORMANCES IN BUFFALO SPECIES (BUBALUS BUBALIS)
No full textThe importance and competitiveness of buffalo breeding in Italy, compared with the other more established forms of livestock rearing, is demonstrated by the increase
in the national and world buffalo population. The ever-growing trend of milk request and the necessity to cut down fixed production costs make necessary the use of biotechnologies of reproduction, such as artificial insemination (AI) and in vitro embryo production associated to ovum pick-up (OPU), that consent to plan selective directions in short time. A major limiting factor that affect the efficiency of innovative reproductive technologies in buffalo is the seasonality of the species which results in a high incidence of embryonic mortality. This study provides an overview on the effects of season on reproductive performances in Mediterranean Italian buffalo at Italian latitudes
Estudio de la influencia de la morfología y de la distribución de tamaños de partícula del polvo en la obtención de aleaciones base Cu y base Ni mediante la tecnología MIM
No full textEn las últimas dos décadas, el procesado mediante moldeo por inyección de polvos metálicos (MIM) ha sido una tecnología que ha experimentado un notable crecimiento año tras año debido a que constituye una alternativa rentable para la fabricación de piezas de pequeño tamaño y difícil geometría. Sin embargo, una de sus mayores limitaciones como tecnología es el alto coste que presentan los polvos metálicos con morfología esférica y pequeño tamaño de partícula que se utilizan normalmente en esta ruta de procesado. En el presente trabajo de investigación se ha estudiado la influencia de la morfología del polvo metálico y de la distribución de tamaños de partícula del mismo sobre cada una de las etapas que constituyen el procesado MIM. El objetivo principal es determinar la viabilidad de la sustitución total o parcial del tipo de polvo que se utiliza actualmente (atomizado en gas) por otros tipos de polvo más económicos. Para llevar a cabo este estudio, se seleccionaron dos materiales metálicos cuyo procesado mediante MIM presentara interés industrial. Se eligió un bronce (90Cu/10Sn) y una superaleación base níquel (Inconel 718). Ambos materiales fueron mezclados con un ligante formado por polietileno de alta densidad (HDPE) y cera parafínica utilizando además, en el caso del Inconel 718, ácido esteárico como agente surfactante. Este sistema ligante multicomponente es económicamente asequible y su abastecimiento está garantizado en el tiempo por lo que constituye una solución adecuada para su aplicación industrial. En la fabricación de las mezclas polvo-ligante se han utilizado polvos de diferente geometría y distribuciones de tamaño de partícula distinta. Por un lado se busca reducir el precio del “feedstock” (mezcla polvo-ligante) y, por otro, aumentar el empaquetamiento para reducir la viscosidad de las mezclas consiguiendo de este modo aumentar la carga sólida y mejorar el control dimensional sobre los componentes. Medidas reológicas y del par de torsión permitieron evaluar el contenido de polvo óptimo de cada mezcla polvoligante para llevar a cabo el proceso de moldeo del material. Además, el estudio de diferentes parámetros reológicos como la viscosidad, el índice de flujo, la energía de activación y el esfuerzo umbral ha permitido determinar cómo influye la morfología y distribución de tamaños de partícula del polvo sobre su procesabilidad. Una vez determinados los contenidos de polvo óptimos en cada caso, se procedió a la fabricación de componentes en verde (formados por el polvo metálico y el ligante) mediante moldeo por inyección de las diferentes mezclas. Para realizar una inyección satisfactoria fue necesario optimizar parámetros como la temperatura, el volumen, la presión y el flujo de inyección de modo que las piezas obtenidas no presentaran defectos de fabricación y fueran lo suficientemente resistentes para soportar la manipulación necesaria en las etapas posteriores. Al mismo tiempo, se estudió la facilidad de procesado de cada mezcla relacionándola con las características del polvo utilizado en cada caso. A continuación, se intentó determinar cuáles eran las técnicas de eliminación del ligante más convenientes teniendo en cuenta los materiales y los sistemas ligantes utilizados. A través de la caracterización térmica (TGA, DSC) del sistema ligante y de los “feedstocks” fabricados, se definieron las condiciones más adecuadas para llevar a cabo el proceso y, del mismo modo que en los casos anteriores, se estudió cómo influyen las características del polvo en el proceso de eliminación. Finalmente, se realizó la sinterización de los materiales, determinando las condiciones óptimas del proceso. Las piezas obtenidas fueron estudiadas evaluando algunas propiedades físicas y mecánicas como la densidad, porosidad y la dureza. Tanto el proceso de sinterización como las propiedades finales fueron relacionados con las características del polvo de partida. ________________________________________________In the present Ph. D thesis, the influence of particle morphology and size distribution
of the powder on the different stages of Powder Injection Moulding process (PIM) has
been investigated. The aim of this work is to determine the optimal powder characteristics
to carry out the process, just as to study the viability of the total or partial replacing of the
gas atomised powder, nowadays used in this technology, with other kinds of more
economical powders.
The study was performed using different bronze (90Cu/10Sn) and superalloy Inconel
718 powders in order to fabricate powder-binder mixtures employing different particle
morphologies and particle size distributions.
The rheological properties determination of the powder-binder mixtures allowed
knowing the optimal solids loading for the green components fabrication through injection
moulding. Next, the more convenient conditions to carry out the binder elimination process
were established and sintering of the materials was performed under different
atmospheres and thermal cycles. Finally, the sintered components were characterized and
the results were compared having into account the features of the powder used for their
fabrication
Studies on in vitro human T cell reactivity to antigens of mycobacterium tuberculosis
No full textStudies on Mycobacterium tuberculosis (MTB) antigens are important to improve immunodiagnostics and vaccine efficacy. A novel genome based strategy for antigen discovery is to relate what is highly expressed by bacilli in vivo or in vitro, to what is recognized by human T cells as antigens. As hypoxia is a relevant stimulus that MTB encounters in vivo, whole genome based transcriptional profiles of M. tuberculosis subject to prolonged hypoxia (described as the Enduring hypoxic response (EHR) were analyzed, to guide the discovery of novel potential anitgens, by a combined bioinformatic and empirical approach and to determine evidence of infection stage specific recognition
Molecular and developmental analysis of non-coding RNA metabolism in" C. elegans" : the exoribonuclease XRN2 and the RNA- binding proteins SART-3 and USIP-1
No full textAbout three quarters of a eukaryotic genome are transcribed into RNA. However, only <2% of these transcripts are translated into protein while the bulk of transcripts execute their biological function as RNA. Non-protein coding RNAs (ncRNAs) associate with proteins in ribonucleoprotein particles (RNPs) to regulate gene expression at various stages thereby greatly increasing the functional complexity of the genome. Nonetheless, the function and mode of action of the vast majority of ncRNAs is unknown and even in well studied examples little is known about the post-transcriptional regulation of ncRNAs themselves. In the thesis at hand, I explored the molecular and developmental functions of proteins implicated in the metabolism of ncRNAs, namely the miRNA-degrading enzyme XRN2 and the U6 snRNA-interacting proteins SART-3 and USIP-1. The XRN2 project was a collaboration with Takashi Miki and Hannes Richter.
XRN2 project
XRN2 is a conserved 5’-to-3’ exoribonuclease involved in various pathways including transcription termination and processing of precursor forms of rRNAs and snoRNAs. Our lab had established a function of XRN2 in the turnover of mature miRNAs, however, whether XRN2 targets all or specific miRNAs in vivo remained unclear. Although XRN2 substrates have extensively been characterized, the developmental function of XRN2 is essentially unexplored. Moreover, knowledge of co-factors regulating XRN2 function beyond transcription termination is scarce in multicellular organisms. In order to elucidate the developmental role of XRN2, we characterized an xrn-2 null and xrn-2 temperature-sensitive mutant. We found that XRN2 is essential during several stages of C. elegans development, including embryogenesis, and that only specific miRNAs are affected by XRN2 in vivo. Co-immunoprecipitations identified PAXT-1 (PArtner of XRN-Two 1) as a tight interaction partner of XRN2. paxt-1 depletion enhanced the xrn-2ts mutant phenotype and a paxt-1 null mutant slowed-down miRNA degradation in vivo, similar to XRN2 inactivation. These observations, as we showed, are due to a stabilizing effect of PAXT-1 on XRN2. Truncation mutants of PAXT-1 revealed a conserved N-terminal domain of unknown function, DUF3469, sufficient for XRN2 binding. We were excited to discover that human proteins containing DUF3469 were also able to bind to XRN2. Hence, we renamed DUF3469 to XRN2-binding domain (XTBD). Collectively, we identified PAXT-1 as an essential interaction partner of XRN2 in C. elegans and established a protein domain (XTBD) that serves as a binding platform for XRN2 beyond C. elegans.
Finally, the laboratory of Dr. Martin Simard found that the scavenger decapping enzyme DCS-1 interacts with the exonuclease XRN1, a paralogue of XRN2, to promote miRNA degradation in C. elegans. Collaborating on their project, I evaluated the subcellular localization of XRN1 and XRN2 in C. elegans and provided tools useful to their experiments such as an XRN1 antibody. This collaborative work has been published and can be found in section 7.
SART-3 project
The human protein SART3 and its yeast homolog Prp24 have previously been implicated in spliceosome assembly, namely the association of the U4 and U6 snRNP into the U4/U6 di-snRNP complex. Additionally, a physical interaction of SART3 with the Argonaute proteins AGO1 and AGO2 had been reported, suggesting an involvement of SART3 in the miRNA pathway. However, a putative function of SART3 in the miRNA pathway remained to be established. In order uncover such a function and to shed light on the so far largely neglected systemic role of SART3 in a multicellular context, I investigated its C. elegans homolog SART-3. Co-immunoprecipitations of SART-3 revealed an interaction with a previously uncharacterized putative terminal uridylyl transferase (TUTase), whereas I could not verify an interaction between SART-3 and AGO1/AGO2. It is known that SART3 binds specifically to the U6 snRNA which contains a post-transcriptionally elongated uridine (U)-tail essential for spliceosome assembly. Therefore it was appealing to assume that this U-tail is polymerized by the identified TUTase. Subsequent analyses unveiled an interaction between the TUTase and U6 snRNA, which hence was renamed to U Six snRNA Interacting Protein 1 (USIP-1). It appeared that USIP-1 binds to a U6 snRNA species that is devoid of Lsm proteins suggesting a role for USIP-1 early in spliceosome assembly. Moreover, knock-down of sart-3 in a usip-1 null mutant background led to a synthetic, embryonic lethal phenotype. This phenotype was rescued by transgenic expression of wild-type USIP-1. Although formal demonstration of TUTase-activity for USIP-1 is lacking, the synthetic lethality was not rescued by a supposedly catalytically inactive version of USIP-1. In sum, I established a physical and functional interaction between two previously uncharacterized proteins in C. elegans, SART-3 and USIP-1, and explored their developmental phenotypes
Estudo da atividade biológica de Baccharis articulata, Musa x paradisiaca e rutina na homeostasia da glicose em modelos experimentais in vivo e in vitro
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em FarmáciaA insulina é o principal hormônio anabólico responsável pelo controle da captação, utilização e armazenamento dos nutrientes celulares como carboidratos, proteínas e lipídios, sendo essencial para a manutenção da homeostasia da glicose, o crescimento e diferenciação celular. Defeitos na ação e/ou na secreção de insulina podem levar à hiperglicemia, característica da diabetes melito. A diabetes melito é uma patologia complexa e multifatorial de elevada morbidade e mortalidade e, por esse motivo, é considerada uma epidemia, caracterizando um problema de saúde pública mundial. Muitas plantas são conhecidas na medicina popular de diferentes culturas pelas propriedades hipoglicemiantes e tem um uso crescente no tratamento da diabetes. Os compostos fenólicos derivados de plantas, especialmente os flavonóides, apresentam diversas propriedades e tem um potencial terapêutico muito investigado. O presente trabalho teve como objetivo caracterizar o efeito de extratos e frações de Bacharis articulata (carqueja) e de Musa x paradisiaca (banana), assim como do flavonóide rutina, na homeostasia da glicose em modelos experimentais in vivo e in vitro. As duas espécies foram avaliadas quanto às atividades anti-hiperglicêmica e/ou hipoglicemiante na curva de tolerância à glicose e em modelos de diabetes induzidos experimentalmente, como a secreção de insulina, o conteúdo de glicogênio hepático e muscular, a inibição das enzimas ?-glicosidases e a propriedade anti-glicação, assim como o conteúdo de flavonóides. Além disso, foi estudado o mecanismo de ação da rutina na captação de glicose e de cálcio em músculo sóleo, e também a secreção de insulina in vivo e o mecanismo de ação da rutina na captação de cálcio em ilhotas pancreáticas isoladas. Para tanto, foram utilizados ratos Wistar machos entre 50-55 dias de idade. Para a realização da curva de tolerância à glicose as coletas de sangue, para determinação da glicose e insulina sérica, foram realizadas nos tempos zero, 15, 30, 60, 120 e 180 minutos. Nos ensaios para a determinação do conteúdo de glicogênio os tecidos foram retirados dos animais 3 h após os tratamentos. As atividades das dissacaridases intestinais e a propriedade anti-glicação foram realizadas in vitro. A captação de 14C-glicose e de 45-cálcio (45Ca2+) foi estudada após a incubação do músculo sóleo com a rutina. As ilhotas pancreáticas foram isoladas e incubadas com 45Ca2+ e rutina, na presença ou não de diferentes inibidores e ativadores. Os extratos brutos, as frações n-butanol e residual aquosa de B. articulata e de M. x paradisiaca reduziram significativamente a glicemia de ratos normais hiperglicêmicos e potencializaram a secreção de insulina induzida por glicose. Além disso, observou-se um aumento no conteúdo de glicogênio no músculo sóleo e fígado após os tratamentos, principalmente com as frações n-butanol das duas espécies vegetais. Os extratos e as frações reduziram a atividade da maltase e preveniram a glicação. A rutina estimulou a captação de glicose e cálcio no músculo, estimulando a captação de glicose através da ativação de uma via insulinomimética e uma via independente da sinalização clássica da insulina. Além disso, a rutina estimulou a secreção de insulina in vivo e a captação de cálcio em ilhotas pancreática isoladas, atuando como um potencial agente secretagogo de insulina. Desta forma, apoiado nos resultados obtidos neste trabalho, propõe-se que as espécies vegetais, Baccharis articulata e Musa x paradisiaca, e o flavonóide rutina aqui estudados possam regular a homeostasia da glicose. Os mecanismos envolvem a inibição da enzima que permite a absorção intestinal da glicose, a inibição da glicação, o estímulo da secreção de insulina e o aumento na utilização de glicose pelos tecidos periféricos, evidenciando que estas duas espécies e a rutina podem atuar por múltiplos mecanismos de ação para regular a homeostasia da glicose e colaborar na prevenção das complicações da diabetes.Insulin is the main anabolic hormone responsible for controlling the uptake, use and storage of cellular nutrients such as carbohydrates, proteins and lipids. It is essential for the maintenance of glucose homeostasis, growth and cellular differentiation. Defects in action and / or secretion of insulin may lead to hyperglycemia, which characterizes diabetes mellitus. Diabetes mellitus is a complex and multifactorial disease with high morbidity and mortality, therefore is considered epidemic causing a public health problem worldwide. Many plants are known in folk medicine of different cultures for their hypoglycemic properties showing an increasing use in the treatment of diabetes. The plant-derived phenolic compounds, especially flavonoids, have several properties and their therapeutic potential has been investigated. The aim of this study was to characterize the effect of extracts and fractions of Baccharis articulata ("carqueja") and Musa x paradisiaca ("banana"), as well as the flavonoid rutin, in glucose homeostasis using in vivo and in vitro experimental models. Antihyperglycemic and / or hypoglycemic activity in the curve of glucose tolerance and in models of experimentally induced diabetes, insulin secretion, the hepatic glycogen content and muscle, inhibition of the enzymes á-glucosidases and anti-glycation property were investigated, as well as the content of flavonoids. In addition, was also studied the mechanism of action of rutin in glucose and calcium uptake in soleus muscle, and also the in vivo insulin secretion and the mechanism of action of rutin on calcium uptake in rat isolated pancreatic islets. For in vivo experiments, Wistar male rats with 50-55 days of age were used. To glycemia and serum insulin determination blood samples were collected at zero, 15, 30, 60, 120 and 180 min in glucose tolerance curve. Tissues were removed from animals 3 h after oral administration of treatments to determine glycogen contents. The intestinal disaccharidases activities and anti-glycation property were performed in vitro. The glucose and calcium uptake was studied after incubation of the soleus muscle with rutin, in the presence or not of different inhibitors and of 14C-glucose or calcium (45Ca2+). The pancreatic islets were isolated and incubated with 45Ca2+ and rutin in the presence or absence of various inhibitors or activators. The crude extracts and n-butanol and residual aqueous fractions of B. articulata and of M. x paradisiaca showed potential anti-hyperglycemic activity in hyperglycemic normal rats and potentiated glucose-induced insulin secretion. Additionaly, it was observed an increase on glycogen content in muscle and liver after treatments, mainly with the n-butanol fractions of two species. The extracts and fractions reduced the activity of maltase and prevented glycation. Also, rutin stimulated glucose and calcium uptake in soleus muscle, stimulating glucose uptake via activation of an insulin-mimetic and an insulin-independent signaling pathways. Additionally, rutin stimulated insulin secretion in vivo and calcium uptake in isolated pancreatic islets, as a potential insulin secretagogue agent. Thus, these results suggest that Baccharis articulata, M. x paradisiaca and rutin are able to regulate glucose homeostasis. The mechanisms involve the inhibition of the enzyme that allows the intestinal absorption of glucose, the inhibition of glycation, the stimulation of insulin secretion and increase in glucose utilization by peripheral tissues showed that these plant species and rutin may act by multiple mechanisms of action to regulate glucose homeostasis, thereby contributing to the prevention of diabetes-related complications
LRRK2 genetics and expression in the Parkinsonian brain
No full textMutations in LRRK2 have been established as a common genetic cause of Parkinson’s
disease (PD). Variation in gene expression of PARK loci has previously been
demonstrated in PD pathogenesis, although it has not been described in detail for
LRRK2 expression in the human brain. This study further elucidates the role of
LRRK2 in development of PD by describing an investigation into the role of LRRK2
genetics and expression in the human brain.
The G2019S mutation is a common LRRK2 mutation that exhibits a clinical and
pathological phenotype indistinguishable from idiopathic PD. Thus, the study of
G2019S mutation is a recurrent theme. The frequency of G2019S was estimated in
unaffected subjects that lived or shared a cultural heritage to the predicted founding
populations of the mutation, and was found not to be common in these populations.
Morphological analysis revealed a ubiquitous expression for LRRK2 mRNA and
protein in the human brain. In-situ hybridisation data suggests that LRRK2 mRNA is
present as a low copy number mRNA in the human brain. A semi-quantitative
analysis of LRRK2 immunohistochemistry revealed extensive regional variation in
the LRRK2 protein levels, although the weakest immunoreactivity was consistently
identified in the nigrostriatal dopamine region. No difference was observed in the
morphological localisation of LRRK2 mRNA and protein in unaffected, IPD or
G2019S positive PD subjects.
Dysregulation of LRRK2 mRNA expression and the effects of cis- acting genetic
variation on these levels were demonstrated. A widespread decrease of LRRK2
mRNA was observed in IPD and G2019S positive PD subjects in comparison to
unaffected controls. Furthermore, non-coding genetic variation was also
demonstrated to have an effect on the LRRK2 transcriptional activity in PD subjects.
Collectively, these findings suggest that LRRK2 has an important physiological role,
and a dysregulation in its levels could affect auxiliary mechanisms that contribute to
PD pathogenesis. This data also supports the possibility of a shared mechanism
contributing to the identical phenotype of IPD and G2019S linked PD
The dramaturgy of ritual performances in Indian parliamentary debates
No full textThe content, style and form of MPs' performances on the floor of both Houses of the
Indian Parliament has undergone dramatic change within the last decade. For example,
97% of the productive hours of the Winter (Nov-Dec) 2010 Session were lost due to
intense disruption by MPs across the political spectrum seeking to stall the House.
Moreover, an increasing number of Bills are debated for less than an hour, if at all, on
the floor of Parliament - raising the conceptual question of whether legislation can still
be considered one of parliament's key functions in India. These changes require, at the
very least, an attempt to re-conceptualize the meaning and significance attributed to
various tropes of parliamentary performances, including those which seemingly subvert
all notions of parliamentary procedure, decorum and etiquette. In my thesis, I adopt a
novel interdisciplinary analytical framework, drawing upon performance studies, microsociological
dramaturgy of face-to-face interaction, interpretations of procedural
invocations, rhetorical political analysis and the study of political rituals. My primary
research question was whether the concept of ritual could usefully be mapped onto
performances of debates in the Indian parliamentary context. I then asked what the
significance of the absence or presence of rituals in this context would mean. Two case
were studies selected for this analysis, namely the Prevention of Terrorism Act (2001-
2004) and the Women's Reservation Bill (1996-2011), informed by a more general
ethnography of the Indian Parliament undertaken for this research. Both studies were
chosen using the logic of 'extreme case study selection' as these performances exhibit
extreme forms of dramaturgical violence, protest and polarized rhetoric that is
increasingly reflective of the everyday performances of the Indian Parliament. In my
research, I have adopted an interpretivist-constructivist approach to the ethnographic
method and have conducted two tranches of field research in New Delhi for that
purpose. My analysis demonstrates the presence of a diverse range of rituals of debate
being performed simultaneously during the legislative process within the Indian
Parliament, namely, procedural rituals, interpersonal rituals and disruptive rituals. These
findings corroborate the broader argument that the study of rituals are integral to an
understanding of parliamentary processes. Moreover, instead of dismissing certain
aspects of performance (e.g. physical obstruction of debate) as being symptomatic of
what many scholars have called the 'decline of parliament', my findings support the
cause for re-signifying, or re-reading parliamentary disruption as supporting, rather than
diminishing, the processes of political representation and widening the spectrum of
forms of political action considered as legitimate modes of political deliberation. The
evolution of these newer, sometimes disruptive, forms of representative ritual can be
read into wider processes of vernacularization and mediatization currently transforming
the ethos, identity and modus operandi of the Indian Parliament
