122 resultados para edentulous ridge expansion
Resumo:
Mit dem vorliegenden Aufsatz untersuchen wir, wie sich die Expansion des staatlichen Sektors in den 60er und 70er Jahren auf den Arbeitsmarkt ausgewirkt hat. Wir gehen dieser Frage dabei aus der Perspektive der Berufsverläufe der aufeinander folgenden Geburtenjahrgänge 1929-31, 1939-41 und 1949-51 nach, die sich während dieses Beschäftigungsausbaus in unterschiedlichen Phasen ihrer beruflichen Karriere befunden haben. Die Grundlage der Analyse stellen dabei retrospektive Längsschnittdaten über die Erwerbsverläufe dieser Geburtskohorten dar. Wir zeigen, daß in den 60er und 70er Jahren vor allem die qualifizierten Arbeitskräfte von der staatlichen Expansion profitiert haben, die in dieser Zeit gerade in den Arbeitsmarkt eingetreten sind. Diese Geburtenjahrgänge konnten die vom staatlichen Sektor geforderten höheren formalen Qualifikationen erwerben und waren nicht, wie bereits längere Zeit in der Privatwirtschaft Beschäftigte durch berufliche und institutionelle Barrieren zwischen beiden Sektoren in ihrer Mobilität beschränkt. Die staatliche Expansion hat deswegen zu bildungs- und kohortenspezifisch höchst unterschiedlichen Chancen geführt. Im Zuge der staatlichen Personalexpansion verstärkte sich die Verbindung zwischen dem höheren Bildungssystem und den leitenden Funktionen im öffentlichen Dienst. Insbesondere der Zuwachs von Akademikern wurde in den 60er und 70er Jahren fast vollständig vom staatlichen Sektor aufgenommen. Aus den Analysen ergibt sich die Vermutung, daß von der restriktiven Personalpolitik des Staates in den 80er Jahren vor allem die jungen und qualifizierten Arbeitskräfte betroffen sein dürften.
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We introduce a justification logic with a novel constructor for evidence terms, according to which the new information itself serves as evidence for believing it. We provide a sound and complete axiomatization for belief expansion and minimal change and explain how the minimality can be graded according to the strength of reasoning. We also provide an evidential analog of the Ramsey axiom.
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Range expansions are extremely common, but have only recently begun to attract attention in terms of their genetic consequences. As populations expand, demes at the wave front experience strong genetic drift, which is expected to reduce genetic diversity and potentially cause ‘allele surfing’, where alleles may become fixed over a wide geographical area even if their effects are deleterious. Previous simulation models show that range expansions can generate very strong selective gradients on dispersal, reproduction, competition and immunity. To investigate the effects of range expansion on genetic diversity and adaptation, we studied the population genomics of the bank vole (Myodes glareolus) in Ireland. The bank vole was likely introduced in the late 1920s and is expanding its range at a rate of ~2.5 km/year. Using genotyping-by-sequencing, we genotyped 281 bank voles at 5979 SNP loci. Fourteen sample sites were arranged in three transects running from the introduction site to the wave front of the expansion. We found significant declines in genetic diversity along all three transects. However, there was no evidence that sites at the wave front had accumulated more deleterious mutations. We looked for outlier loci with strong correlations between allele frequency and distance from the introduction site, where the direction of correlation was the same in all three transects. Amongst these outliers, we found significant enrichment for genic SNPs, suggesting the action of selection. Candidates for selection included several genes with immunological functions and several genes that could influence behaviour.
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Foxp3+ regulatory T (Treg) cells are essential for the maintenance of immune homeostasis and tolerance. During viral infections, Treg cells can limit the immunopathology resulting from excessive inflammation, yet potentially inhibit effective antiviral T cell responses and promote virus persistence. We report here that the fast-replicating LCMV strain Docile triggers a massive expansion of the Treg population that directly correlates with the size of the virus inoculum and its tendency to establish a chronic, persistent infection. This Treg cell proliferation was greatly enhanced in IL-21R-/- mice and depletion of Treg cells partially rescued defective CD8+ T cell cytokine responses and improved viral clearance in some but not all organs. Notably, IL-21 inhibited Treg cell expansion in a cell intrinsic manner. Moreover, experimental augmentation of Treg cells driven by injection of IL-2/anti-IL-2 immune complexes drastically impaired the functionality of the antiviral T cell response and impeded virus clearance. As a consequence, mice became highly susceptible to chronic infection following exposure to low virus doses. These findings reveal virus-driven Treg cell proliferation as potential evasion strategy that facilitates T cell exhaustion and virus persistence. Furthermore, they suggest that besides its primary function as a direct survival signal for antiviral CD8+ T cells during chronic infections, IL-21 may also indirectly promote CD8+ T cell poly-functionality by restricting the suppressive activity of infection-induced Treg cells.
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Despite the numerous available possibilities for the surgical treatment of peripheral nerve lesions found in the dog, the success of these treatments is often unsatisfactory. It has been proven that Schwann cells (SC) have a positive influence on the regeneration of nerve stumps. Implanting a guidance channel seeded with autologous SC at the lesion site could be a new therapeutic approach. The aim of this research was to investigate the in vitro cultivation and expansion of canine SC as the main requirement for the treatment referred to above. Biopsies were carried out on 17 nerve samples originating from dogs of different breed, age, gender and condition. The reexplantation method was employed, followed by dissociation using hyaluronidase, collagenase and trypsin and further expansion. The samples were divided into six groups which were treated with a varying combination of mitogens (forskolin, bovine PEX, choleratoxin, heregulin). To obtain the quantities of SC, the specimens were immunostained by a p75-antibody. By employing a growing number of agents it was possible to obtain an increase in both the quantity of cells and purity of cultures. A maximum of 16x10(5) cells per millilitre of suspension was achieved. The largest SC purity measured 27.1%. The maximum SC quantity achieved was 43.3x10(4) SC per millilitre.
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A precise radiographic evaluation of the local bone dimensions and morphology is important for preoperative planning of implant placement. The purpose of this retrospective study was to analyze dimensions and morphology of edentulous sites in the posterior mandible using cone beam computed tomography (CBCT) images. This retrospective radiographic study measured the bone width (BW) of the mandible at three locations on CBCT scans for premolars (PM1, PM2) and molars (M1, M2): at 1 mm and 4 mm below the most cranial point of the alveolar crest (BW1, BW2) and at the superior border of the mandibular canal (BW3). Furthermore, the height (H) of the alveolar process (distance between the measuring points BW1 and BW3), as well as the presence of lingual undercuts, were analyzed. A total of 56 CBCTs met the inclusion criteria, resulting in a sample size of 127 cross sections. There was a statistically significant increase from PM1 to M2 for the BW2 (P < .001), which was not present for BW1 and BW3 values. For the height of the alveolar process, the values exhibited a decrease from PM1 to M2 sites. Sex was a statistically significant parameter for H (P = .001) and for BW1 (P = .03). Age was not a statistically significant parameter for bone width (BW1: P = .37; BW2: P = .31; BW3: P = .51) or for the height of the alveolar process (P = .41) in the posterior mandible. Overall, 73 (57.5%) edentulous sites were evaluated to be without visible lingual undercuts; 13 (10.2%) sites exhibited lingual undercuts classified as influential for implant placement. Precise evaluation of the alveolar crest by cross-sectional imaging is of great value to analyze vertical and buccolingual bone dimensions in different locations in the posterior mandible. In addition, CBCTs are valuable to diagnosing the presence of and potential problems caused by lingual undercuts prior to implant placement.
Resumo:
PURPOSE To systematically review clinical studies examining the survival and success rates of implants in horizontal ridge augmentation, either prior to or in conjunction with implant placement in the anterior maxilla. MATERIALS AND METHODS A literature search was undertaken up to September 2012 including clinical studies in English with ≥ 10 consecutively treated patients and a mean follow-up of at least 12 months. Two reviewers screened the pertinent articles and extracted the data. Key words focused on the outcome parameters (implant success, implant survival, horizontal bone gain, and intra- and postoperative complications) in studies utilizing either a simultaneous approach (ridge augmentation performed at the time of implant placement) or a staged approach (ridge augmentation performed prior to implant placement) were analyzed. RESULTS A total of 13 studies met the inclusion criteria, with 2 studies in the simultaneous group and 11 studies in the staged group. In the simultaneous group, survival rates of implants were 100% in both studies, with one study also reporting a 100% implant success rate. No data on horizontal bone gain were available. In the staged group, success rates of implants placed in horizontally augmented ridges ranged from 96.8% to 100% (two studies), and survival rates ranged from 93.5% to 100% (five studies). However, follow-up periods differed widely (up to 4.1 years). Mean horizontal bone gain determined at reentry (implant placement) ranged from 3.4 to 5.0 mm with large overall variations (0 to 9.8 mm, five studies). Intraoperative complications were not reported. Postsurgical complications included mainly mucosal dehiscences (five studies), and, occasionally, complete failures of block grafts were described in one study. CONCLUSIONS Staged and simultaneous augmentation procedures in the anterior maxilla are both associated with high implant success and survival rates. The level of evidence, however, is better for the staged approach than for the simultaneous one.
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PURPOSE To evaluate and compare crestal bone level changes and peri-implant status of implant-supported reconstructions in edentulous and partially dentate patients after a minimum of 5 years of loading. MATERIALS AND METHODS All patients who received a self-tapping implant with a microstructured surface during the years 2003 and 2004 at the Department of Prosthodontics, University of Bern, were included in this study. The implant restorations comprised fixed and removable prostheses for partially and completely edentulous patients. Radiographs were taken immediately after surgery, at impression making, and 1 and 5 years after loading. Crestal bone level (BIC) was measured from the implant shoulder to the first bone contact, and changes were calculated over time (ΔBIC). The associations between pocket depth, bleeding on probing (BOP), and ΔBIC were assessed. RESULTS Sixty-one implants were placed in 20 patients (mean age, 62 ± 7 years). At the 5-year follow-up, 19 patients with 58 implants were available. Implant survival was 98.4% (one early failure; one patient died). The average ΔBIC between surgery and 5-year follow-up was 1.5 ± 0.9 mm and 1.1 ± 0.6 mm for edentulous and partially dentate patients, respectively. Most bone resorption (50%, 0.7 mm) occurred during the first 3 months (osseointegration) and within the first year of loading (21%, 0.3 mm). Mean annual bone loss during the 5 years of loading was < 0.12 mm. Mean pocket depth was 2.6 ± 0.7 mm. Seventeen percent of the implant sites displayed BOP; the frequency was significantly higher in women. None of the variables were significantly associated with crestal bone loss. CONCLUSION Crestal bone loss after 5 years was within the normal range, without a significant difference between edentulous and partially dentate patients. In the short term, this implant system can be used successfully for various prosthetic indications.
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In this study, we assess the climate mitigation potential from afforestation in a mountainous snow-rich region (Switzerland) with strongly varying environmental conditions. Using radiative forcing calculations, we quantify both the carbon sequestration potential and the effect of albedo change at high resolution. We calculate the albedo radiative forcing based on remotely sensed data sets of albedo, global radiation and snow cover. Carbon sequestration is estimated from changes in carbon stocks based on national inventories. We first estimate the spatial pattern of radiative forcing (RF) across Switzerland assuming homogeneous transitions from open land to forest. This highlights where forest expansion still exhibits climatic benefits when including the radiative forcing of albedo change. Second, given that forest expansion is currently the dominant land-use change process in the Swiss Alps, we calculate the radiative forcing that occurred between 1985 and 1997. Our results show that the net RF of forest expansion ranges from −24 W m−2 at low elevations of the northern Prealps to 2 W m−2 at high elevations of the Central Alps. The albedo RF increases with increasing altitude, which offsets the CO2 RF at high elevations with long snow-covered periods, high global radiation and low carbon sequestration. Albedo RF is particularly relevant during transitions from open land to open forest but not in later stages of forest development. Between 1985 and 1997, when overall forest expansion in Switzerland was approximately 4%, the albedo RF offset the CO2 RF by an average of 40%. We conclude that the albedo RF should be considered at an appropriately high resolution when estimating the climatic effect of forestation in temperate mountainous regions.
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The reciprocal interaction between cancer cells and the tissue-specific stroma is critical for primary and metastatic tumor growth progression. Prostate cancer cells colonize preferentially bone (osteotropism), where they alter the physiological balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption, and elicit prevalently an osteoblastic response (osteoinduction). The molecular cues provided by osteoblasts for the survival and growth of bone metastatic prostate cancer cells are largely unknown. We exploited the sufficient divergence between human and mouse RNA sequences together with redefinition of highly species-specific gene arrays by computer-aided and experimental exclusion of cross-hybridizing oligonucleotide probes. This strategy allowed the dissection of the stroma (mouse) from the cancer cell (human) transcriptome in bone metastasis xenograft models of human osteoinductive prostate cancer cells (VCaP and C4-2B). As a result, we generated the osteoblastic bone metastasis-associated stroma transcriptome (OB-BMST). Subtraction of genes shared by inflammation, wound healing and desmoplastic responses, and by the tissue type-independent stroma responses to a variety of non-osteotropic and osteotropic primary cancers generated a curated gene signature ("Core" OB-BMST) putatively representing the bone marrow/bone-specific stroma response to prostate cancer-induced, osteoblastic bone metastasis. The expression pattern of three representative Core OB-BMST genes (PTN, EPHA3 and FSCN1) seems to confirm the bone specificity of this response. A robust induction of genes involved in osteogenesis and angiogenesis dominates both the OB-BMST and Core OB-BMST. This translates in an amplification of hematopoietic and, remarkably, prostate epithelial stem cell niche components that may function as a self-reinforcing bone metastatic niche providing a growth support specific for osteoinductive prostate cancer cells. The induction of this combinatorial stem cell niche is a novel mechanism that may also explain cancer cell osteotropism and local interference with hematopoiesis (myelophthisis). Accordingly, these stem cell niche components may represent innovative therapeutic targets and/or serum biomarkers in osteoblastic bone metastasis.
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OBJECTIVE The results of Interventional Management of Stroke (IMS) III, Magnetic Resonance and REcanalization of Stroke Clots Using Embolectomy (MR RESCUE), and SYNTHESIS EXPANSION trials are expected to affect the practice of endovascular treatment for acute ischemic stroke. The purpose of this report is to review the components of the designs and methods of these trials and to describe the influence of those components on the interpretation of trial results. METHODS A critical review of trial design and conduct of IMS III, MR RESCUE, and SYNTHESIS EXPANSION is performed with emphasis on patient selection, shortcomings in procedural aspects, and methodology of data ascertainment and analysis. The influence of each component is estimated based on published literature including multicenter clinical trials reporting on endovascular treatment for acute ischemic stroke and myocardial infarction. RESULTS We critically examined the time interval between symptom onset and treatment and rates of angiographic recanalization to differentiate between "endovascular treatment" and "parameter optimized endovascular treatment" as it relates to the IMS III, MR RESCUE, and SYNTHESIS EXPANSION trials. All the three trials failed to effectively test "parameter optimized endovascular treatment" due to the delay between symptom onset and treatment and less than optimal rates of recanalization. In all the three trials, the magnitude of benefit with endovascular treatment required to reject the null hypothesis was larger than could be expected based on previous studies. The IMS III and SYNTHESIS EXPANSION trials demonstrated that rates of symptomatic intracerebral hemorrhages subsequent to treatment are similar between IV thrombolytics and endovascular treatment in matched acute ischemic stroke patients. The trials also indirectly validated the superiority/equivalence of IV thrombolytics (compared with endovascular treatment) in patients with minor neurological deficits and those without large vessel occlusion on computed tomographic/magnetic resonance angiography. CONCLUSIONS The results do not support a large magnitude benefit of endovascular treatment in subjects randomized in all the three trials. The possibility that benefits of a smaller magnitude exist in certain patient populations cannot be excluded. Large magnitude benefits can be expected with implementation of "parameter optimized endovascular treatment" in patients with ischemic stroke who are candidates for IV thrombolytics.