3,642 research outputs found
Description and molecular diagnosis of a new species of Brunfelsia (Solanaceae) from the Bolivian and Argentinean Andes
Brunfelsia plowmaniana N.Filipowicz & M.Nee sp. nov., a species from humid and cloud forests of the Bolivian and Argentinean Andes, is described and provided with a molecular diagnosis, using provisions available in the recently approved International Code of Nomenclature for algae, fungi and plants. Specimens belonging to the new species were previously placed in the polymorphic B. uniflora (Pohl) D.Don, which a molecular phylogeny revealed as polyphyletic. Revision of numerous collections revealed clear morphological differences between the new species and B. uniflora, the type locality of which is in the state of SĂŁo Paulo, Brazil
The static characteristics of a torsionally flexible metal coupling
The paper presents a description of test stands and the methodology ofdetermining the static characteristics of a metal coupling of high torsional flexibility. In addition, the paper presents preliminary tests results which enable to determine the above characteristics
PĆeÄ autobiograficznego âjaâ. Przypadek RenĂĄty TyrĆĄovej
The aim of this paper, is to try to use feminist and gender theories to read Slavic cultural material, as well as to complete the picture of diversity of Slavic gender orders. For this purpose, the paper focuses on biographies written by RenĂĄta TyrĆĄovĂĄ devoted to her father and husband. The analysis of this case requires using the feminist criticism of autobiography theory, which is hardly theoretically absorbed within Slavistics. Article seeks to explore the complexities of the relationship between female individual autobiographical âselfâ, structure of female gender in the bourgeois society of the 19th century, and finally collective idea of nationalism.The aim of this paper, is to try to use feminist and gender theories to read Slavic cultural material, as well as to complete the picture of diversity of Slavic gender orders. For this purpose, the paper focuses on biographies written by RenĂĄta TyrĆĄovĂĄ devoted to her father and husband. The analysis of this case requires using the feminist criticism of autobiography theory, which is hardly theoretically absorbed within Slavistics. Article seeks to explore the complexities of the relationship between female individual autobiographical âselfâ, structure of female gender in the bourgeois society of the 19th century, and finally collective idea of nationalism
The social dimension of sustainable development
The chapter describes the main challenges for the social dimension of sustainable development, such as inequality, labour conditions and wages, meeting basic needs: food, housing, water, energy, education and health and power relations: political voice and peace and justice. Referring to Doughnut economics an additional difficulty is meeting the above-mentioned challenges without exceeding the ecological ceilings. The chapter in particular discusses issues related to the measurement of the social foundations of sustainable development. The study reviews the basic non-aggregated indicators describing the social dimension. These indicators are components for highly aggregated measures that take into account the social perspective, such as Happy Planet Index (HPI), Sustainable Development Index (SDI), Sustainable Society Index (SSI) or Better Life Index (BLI). The chapter presents both the methodological aspects of measurement and the current data for selected measures of social well-being
Interferon signaling in chronic hepatitis C : mechanisms and implications for therapy
Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide and can lead to liver cirrhosis and hepatocellular carcinoma. The current standard therapy of chronic hepatitis C (CHC) consists of a combination of pegylated interferon alpha (pegIFNα) and ribavirin. However, sustained viral clearance is achieved in only 50-60% of patients. The underlying mechanism of failure of pegIFNα based therapy remains unknown and no molecular or genetic markers have been identified that could predict the treatment outcome. The overall aim of the study described in this thesis is to understand the molecular basis for failure of IFNα based therapies in patients with CHC. The study has focused on the IFNinduced Jak-STAT (janus kinase-signal transducer and activator of transcription) signaling pathway. To address the molecular basis of treatment response to IFN therapy, three experimental approaches have been employed. The first approach involved the analysis of IFNα signaling and expression of interferon stimulated genes (ISGs) in liver biopsies and peripheral blood mononuclear cells (PBMCs) of HCV patients undergoing pegIFNα treatment. Paired liver biopsies and PBMCs from 16 patients were collected before andhours after the first injection of pegIFNα, and were subjected to analysis of global gene expression using Affymetrix arrays. Further, activation of the IFN-induced Jak-STAT signaling pathway was analyzed by immunoblotting, immunohistochemistry and gel shift assays. The correlation of these biochemical and molecular data with the clinical response to treatment demonstrated that in the liver of patients with a rapid response pegIFNα induced a strong upregulation of ISGs, whereas in patients that did not respond to therapy, induction of IFN-dependent gene expression was impaired. Surprisingly, the non-responders had maximally induced ISG expression already before treatment with pegIFNα. Furthermore, the analyses of STAT1 phosphorylation, nuclear localization and DNA binding confirmed that the endogenous IFN signaling pathway in non-responders is pre-activated and refractory to further stimulation. In contrast to liver samples, ISG expression in PBMCs was stimulated by pegIFNα in both responders and nonresponders, indicating that PBMCs are not a good surrogate marker for IFNα responses in the liver and that chronic HCV infection has strong local effects on the IFN system in liver. Our findings support an interesting concept that activation of the endogenous IFN system in CHC not only is ineffective in clearing the infection, but may also impede the response to therapy, most likely by inducing a refractory state of the IFN signaling pathway in the liver.
In the second approach we addressed the mechanisms underlying the pre-activation of the
endogenous IFN system in a defined group of HCV patients (future non-responders). For this
purpose, we analyzed ISG expression by quantitative RT-PCR and nuclear localization of
STAT1 by immunohistochemistry in a cohort of 112 patients with CHC. By subdividing this
cohort according to the HCV genotype (GT), we discovered that patients infected with HCV
GT 1 and 4 more often show hepatic ISG preactivation than GT 2 and 3 patients, thus
providing an explanation for the poor response to IFN therapy seen in GT 1/4 patients. We
analyzed the possible involvement of viral sensory pathways in type I IFN production and
ISG upregulation. Previously, the viral HCV NS3-4A protease was shown to interfere with
viral sensory pathways by cleaving and thereby inactivating an important adaptor molecule,
Cardif. We therefore assessed Cardif cleavage in liver biopsies of HCV patients and found
that cleavage more often occurred in patients infected with HCV GTs 2 and 3. Our findings
support a concept that the success of the virus in preventing the induction of the endogenous
IFN system in the livers of these patients would, however, come at the cost of being more
susceptible to IFNα therapies as is the case with GT 2/3 patients.
In the third approach we designed an experimental model to study the molecular basis of
refractoriness of IFN signaling in vivo. Previously, cell culture experiments demonstrated a
long lasting desensitization period, which followed the initial activation of the IFNα
signaling pathway. In the approach used here, we established a mouse model in which
continuous presence of IFNα in vivo was achieved by multiple subcutaneous injections,
mimicking the constitutively high serum levels achieved by pegIFNα in patients.
Interestingly, this resulted in refractoriness of IFNα signaling. Activation of STAT1 and
STAT2, but not STAT3, in the mouse liver was desensitized by continuous IFNα stimulation.
To elucidate the mechanism of this refractoriness, the role of negative regulators of the Jak-
STAT signaling pathway was investigated. IFN signaling remained refractory in mice
deficient in suppressor of cytokine signaling (SOCS) 3 and persisting refractoriness was also
observed in mice deficient in IL-10, a strong inducer of SOCS3. Ubiquitin specific peptidase
18 (USP18/UBP43) was recently identified as novel negative regulator of IFNα signal
transduction. Interestingly, refractoriness could be overcome in USP18/UBP43 knockout
mice. These data strongly indicate that UBP43 is the decisive factor in inducing a refractory
state in the IFNα signaling pathway in vivo
Understanding the Qualities of an Effective Fieldwork Experience and How it Relates to Pre-service Teachers\u27 Feelings of Self-efficacy and Preparedness
The effectiveness of teacher-preparation programs to produce high-quality teachers has been an issue of concern for a long time. Teachers play a significant role in shaping studentsâ academic achievement and social-emotional growth. Therefore, it is critical to focus on how teacher education programs, especially the field placement component, develop and support new educators. This explanatory mixed-methods study used a theoretical framework of Albert Banduraâs Self-Efficacy Theory (1977) and Pierre Bourdieuâs Cultural Capital Theory (1986) to examine the qualities of an effective practical residency experience and how it relates to preservice teachersâ feelings of self-efficacy and preparedness for teaching diverse students in inclusive school settings. By utilizing online satisfaction surveys and a self-efficacy survey, the research collected data from a pool of 84 pre-service teachers enrolled in a teacher-preparation program in a small, private northeastern university The surveys solicited information regarding the pre-service teachersâ perceptions of the effectiveness of the fieldwork experience and their feelings of self-efficacy and preparedness. Qualitative and mixed-method analysis included interviews with three pre-service teachers. The analysis showed a positive relationship between the perceived effectiveness of the fieldwork experience and the pre-service teachersâ feelings of self-efficacy and preparedness. The findings also indicated the importance of proper fieldwork placement with the support of cooperating teachers and the value of a hands-on approach in the process of learning to teach. The implications of this study highlight the importance of carefully selecting a cooperating teacher who serves as a support for the pre-service teacher. It is recommended to select cooperating teachers who are willing to participate and are trained in working with pre-service teachers and will gradually allow the pre-service teacher more active teaching opportunities. This study adds to the body of existing literature regarding the role of fieldwork experience and its importance in developing pre-service teachersâ self-efficacy and preparedness to teach
On the Phases Structure of the Micromaser System
We investigate, in an exact manner, the phase structure of the micromaser
system in terms of the physical parameters at hand like the atom cavity transit
time, the atom-photon frequency detuning, the number of thermal photons and the
probability for a pump atom to be in its excited state. Phase diagrams are
mapped out for various values of the physical parameters. At sufficiently large
values of the detuning, we find a ``twinkling'' mode of the micromaser system.
A correlation length is used to study fluctuations close to the various phase
transitions.Comment: 4 pages, 4 figure
Kinematic and dynamic simulation of the functioning of torsionally flexible metal coupling
The article presents the process of visualization and the accuracy of performance of the prototype of bidirectional torsionally flexible metal coupling using AutodeskÂź InventorÂź Professional 2009. Selected figures from the simulations are presented and discussed on the basis of a virtual model of the coupling
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