2,383 research outputs found
SCP2, a major protein component of the axial elements of synaptonemal complexes
No full textSynaptonemal complexes (SCs) are ladderlike protein structures, which are formed between homologous chromosomes during the prophase of the first meiotic division. SCs consist of two axial elements, one along each chromosome, and transverse filaments (TFs), which connect the axial elements. On the TFs, between the axial elements, there is a third longitudinal structure, the central element (CE). Possible functions of the axial elements include organization of the chromatin in loops, providing sister chromatid cohesion, stabilization of chiasmata and regulation of recombination. These possible functions are explained in chapter 1 . In axial elements of SCs of rat, two major protein components have been identified, named SCP2 and SCP3, with relative electrophoretic mobilities ( Mr ) of 190,000 and 30,000-33,000. This study mainly focused on the analysis of the function of SCP2.In chapter 2 we describe how we isolated and sequenced the cDNA encoding SCP2 of the rat (rnSCP2). The protein predicted from the nucleotide sequence is basic and has a mass of 173 kDa. At the C-terminus, SCP2 contains a region, which is predicted to be capable of forming a coiled-coil structure. Furthermore, SCP2 contains two clusters of S/T-P motifs, which are common in DNA-binding proteins, and several potential phosphorylation sites. The SCP2 gene is expressed predominantly in meiotic prophase cells.In order to identify conserved domains within SCP2, we isolated and analyzed the human SCP2 cDNA (hsSCP2). This is described in chapter 3 . Although there is only 63% identity at the amino acid level between hsSCP2 and rnSCP2, several structural features and amino acid sequence motifs are conserved; hsSCP2 contains S/T-P motifs, which are commonly found in DNA-binding proteins, in the same domains as rnSCP2 and has a predicted coiled-coil region at its C-terminus. The structural organization of hsSCP2 and rnSCP2 resembles the structural organization of Red1, a protein component of the axial elements in S. cerevisiae . We speculate that Red1 and SCP2 are functional homologues. The hsSCP2 gene was assigned to chromosome 20q13.33 by fluorescence in situ hybridization.The ultrastructural organization of SCP2 and SCP3 within SCs was analyzed by immunogold labeling of surface-spread spermatocytes and sections of testicular tissue as described in chapter 4 . The immunogold-labeling patterns of spreads and sections differed significantly and we attributed this difference to artifacts, caused by the surface-spreading technique. Therefore we relied on sections for the precise localization of SCP2 and SCP3. The immunogold-label distribution of anti-SCP2 and anti-SCP3 antibodies coincided with the axial elements and therefore we conclude that both SCP2 and SCP3 are structural components of the axial elements. The distribution of anti-SCP2 label had a shoulder at the innerside of the axial element, which was not observed with the anti-SCP3 label. Because we observed fuzzy connections between the axial elements that were labeled by anti-SCP2 but not anti-SCP3 antibodies, we attributed the shoulder in the gold label distribution of anti-SCP2 antibodies to the labeling of these connections.To study the localization of SCP2 and SCP3 in successive stages of meiosis, we performed immunofluorescence labeling of dry-down spread preparations of spermatocytes with anti-SCP2 and anti-SCP3 antibodies ( chapter 5 ). SCP2 and SCP3 colocalize along the axial elements from leptotene up till and including diplotene. After diplotene, SCP2 and SCP3 concentrate at the centromeres and small amounts of SCP2 and SCP3 are retained along the chromosome arms until metaphase I. From these results we conclude that both SCP2 and SCP3 are involved in sister chromatid cohesion and chiasma stabilization. SCP2 and SCP3 are furthermore present on connections between desynapsed axial elements in late diplotene. SMC1 and SMC3, which are involved in sister chromatid cohesion during mitosis, and are present in dots along the axial elements during meiosis, are also present along these connections. We think that these connections represent the sites of crossing-over and that they stabilize recombination intermediates between homologous chromosomes, and ensure the continuity of the cores of recombining chromatids.In chapter 6 we consider possible functions of SCP2 and of axial elements.</p
Unstable ironies: narrative instability in Herman Charles Bosman's "Oom Schalk Lourens" series
No full textThis thesis examines the narrative situation within Herman Charles Bosman’s “Oom Schalk Lourens” series of stories, focussing on the nature of the relationship between author and narrator. In particular, it seeks to trace the source of the multiple ironies at work in the texts. It has been customary for critics in the past to claim that the irony within the stories stems from Bosman, operating authorially ‘above’ Oom Schalk. In terms of this theory, Oom Schalk is read as being largely unaware of the inconsistencies and contradictions within his narrative. It is the claim of this thesis, however, that Oom Schalk is the self-aware creator of the texts’ ironies much of the time. Chapter 1 commences with an attempt at defining irony, and provides a brief overview of the history of its deployment within South African literature before discussing the literary genre which Bosman was to exploit as his ironic vehicle: the “oral-style” short story. Chapter 2 examines Wayne C. Booth’s notions of “stable” and “unstable” irony: the irony of the Oom Schalk stories has, in the past, been classified as belonging to the former category, but this thesis attempts to show that its inconsistent deployment within the stories consigns it more accurately to the latter. Chapter 3 offers an assessment of the extrinsic contexts relevant to the analysis: the context of the stories’ publication, and the likely composition of Bosman’s reading public. Chapter 4 begins to examine the distance between implied author and implied narrator in the stories. Chapters 5, 6 and 7 subject stories dealing with the themes of art, race and land to detailed analysis in order to examine the shifting – and progressively, though unevenly, diminishing – distance between Bosman and Oom Schalk. The thesis concludes that the degree to which the ironic distance between author and narrator fluctuates within, and between, the stories, results in a narrative situation which must be classified as fundamentally unstable
Efficacy of the EZ-IO (R) needle driver for out-of-hospital intraosseous access - a preliminary, observational, multicenter study
No full textBackground: Intraosseous (IO) access represents a reliable alternative to intravenous vascular access and is explicitly recommended in the current guidelines of the European Resuscitation Council when intravenous access is difficult or impossible. We therefore aimed to study the efficacy of the intraosseous needle driver EZ-IO(R) in the prehospital setting.
Methods: During a 24-month period, all cases of prehospital IO access using the EZ-IO(R) needle driver within three operational areas of emergency medical services were prospectively recorded by a standardized questionnaire that needed to be filled out by the rescuer immediately after the mission and sent to the primary investigator. We determined the rate of successful insertion of the IO needle, the time required, immediate procedure-related complications, the level of previous experience with IO access, and operator's subjective satisfaction with the device.
Results: 77 IO needle insertions were performed in 69 adults and five infants and children by emergency physicians (n=72 applications) and paramedics (n=5 applications). Needle placement was successful at the first attempt in all but 2 adults (one patient with unrecognized total knee arthroplasty, one case of needle obstruction after placement). The majority of users (92%) were relative novices with less than five previous IO needle placements. Of 22 responsive patients, 18 reported pain upon fluid administration via the needle. The rescuers' subjective rating regarding handling of the device and ease of needle insertion, as described by means of an analogue scale (0 = entirely unsatisfied, 10 = most satisfied), provided a median score of 10 (range 1-10).
Conclusions: The EZ-IO(R) needle driver was an efficient alternative to establish immediate out-of-hospital vascular access. However, significant pain upon intramedullary infusion was observed in the majority of responsive patients
Correction: Corrigendum: Lipopolysaccharide-Induced Neutrophil Dysfunction Following Transjugular Intrahepatic Portosystemic Stent Shunt (TIPSS) Insertion is Associated with Organ Failure and Mortality
No full textScientific Reports 7: Article number: 40157; published online: 04 January 2017; updated: 28 April 2017 Schalk van der Merwe was omitted from the author list in the original version of this Article. This has been corrected in the PDF and HTML versions of the Article, as well as the Supplementary Information that now accompanies this Article.</jats:p
Un capolavoro e le sue immagini sonore. Appunti sulla discografia della Quinta Sinfonia di Beethoven
No full textAnalisi della discografia della Sinfonia n. 5 di Beethoven, con particolare attenzione alle prime registrazioni (A. Nikisch, 1913, R. Strauss, 1928, F. Schalk, 1929), alle edizioni di riferimento nella discografia storica pre-1950 (Toscanini, Furtwängler, Walter) e agli orientamenti dei direttori delle generazioni successive, sino all'avvento delle esecuzioni "filologiche" e ai direttori odierni (Muti, Sinopoli, Abbado, Barenboim)
Macroeconomic effects of the geography of knowledge production: EcoRET, a macroeconometric model with regionally endogenized technological change for Hungary
No full textMainstream economic thinking is still characterized by a predominantly a-spatial theoretical structure. Though economists are able to model the impacts of capital, labor or technology on output, employment or prices at both macro and micro levels, our methodological tools are still not sensitive to the influence of geography on the way inputs contribute to production. Empirical investigations of the relationship between agglomeration and macroeconomic growth are still relatively rare in the literature. It is also a very recent advancement that geographical structure is modeled simultaneously with other variables in macroeconomic models. This paper introduces EcoRET the macroeconometric model with regionally endogenized technological change for Hungary. The unique feature of EcoRET is that it incorporates spatial structure into a traditional macroeconometric model by a regional block of technological change. The model can be applied for policy simulations on the macroeconomic effects of changing geographical distribution of regional financial supports. JEL classification: O31, H41, O40 Keywords: endogenous growth theory, new economic geography, knowledge spillovers, total factor productivity, agglomeration economies
De totstandkoming van meetinstrumenten van empowerment onder de loep: Instrumentontwikkeling volgens de kwaliteitsstandaarden, een kritische beschouwing
No full textEmpowerment is een centraal begrip binnen het sociaal werk in Nederland en Vlaanderen. Er is behoefte aan meetinstrumenten die de empowerende effecten van hulpaanbod blootleggen. De wijze waarop meetinstrumenten ontwikkeld worden, lijkt echter invloed te hebben op de kwaliteit van de instrumenten (Steenssens, Van Regenmortel & Schalk, 2017). Een vijftal kwaliteitsstandaarden is ontwikkeld, waarmee uitspraken gedaan kunnen worden over de kwaliteit van de totstandkoming van dergelijke meetinstrumenten. Om zicht te krijgen op de waarde van deze kwaliteitsstandaarden wordt in dit artikel de wijze waarop een drietal empowerment meetinstrumenten ontwikkeld zijn, kritisch beschouwd vanuit deze standaarden. Dit is gedaan door semigestructureerde interviews met ontwikkelaars te combineren met analyses van bestaand materiaal over de instrumenten. De kwaliteitsstandaarden blijken een kader te bieden met richtlijnen voor instrumentontwikkeling. Het blijkt van belang om goed af te bakenen wat gemeten wordt, zodat een volledig beeld van empowerment verkregen wordt. Verder is goede afstemming tussen contextspecifieke elementen en meer generieke elementen in itemopbouw nodig en is betrokkenheid van de doelgroep bij instrumentontwikkeling noodzakelijk
Caller verification in telecommunication and banking services; the CAVE project
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Author response
No full textSmall GTPases of the Rab family not only regulate target recognition in membrane traffic but also control other cellular functions such as cytoskeletal transport and autophagy. Here we show that Rab26 is specifically associated with clusters of synaptic vesicles in neurites. Overexpression of active but not of GDP-preferring Rab26 enhances vesicle clustering, which is particularly conspicuous for the EGFP-tagged variant, resulting in a massive accumulation of synaptic vesicles in neuronal somata without altering the distribution of other organelles. Both endogenous and induced clusters co-localize with autophagy-related proteins such as Atg16L1, LC3B and Rab33B but not with other organelles. Furthermore, Atg16L1 appears to be a direct effector of Rab26 and binds Rab26 in its GTP-bound form, albeit only with low affinity. We propose that Rab26 selectively directs synaptic and secretory vesicles into preautophagosomal structures, suggesting the presence of a novel pathway for degradation of synaptic vesicles
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